Vulnerabilities (CVE)

Filtered by vendor Linux Subscribe
Total 18222 CVE
CVE Vendors Products Updated CVSS v2 CVSS v3
CVE-2025-21940 1 Linux 1 Linux Kernel 2026-06-17 N/A 5.5 MEDIUM
In the Linux kernel, the following vulnerability has been resolved: drm/amdkfd: Fix NULL Pointer Dereference in KFD queue Through KFD IOCTL Fuzzing we encountered a NULL pointer derefrence when calling kfd_queue_acquire_buffers. (cherry picked from commit 049e5bf3c8406f87c3d8e1958e0a16804fa1d530)
CVE-2025-21939 1 Linux 1 Linux Kernel 2026-06-17 N/A 5.5 MEDIUM
In the Linux kernel, the following vulnerability has been resolved: drm/xe/hmm: Don't dereference struct page pointers without notifier lock The pnfs that we obtain from hmm_range_fault() point to pages that we don't have a reference on, and the guarantee that they are still in the cpu page-tables is that the notifier lock must be held and the notifier seqno is still valid. So while building the sg table and marking the pages accesses / dirty we need to hold this lock with a validated seqno. However, the lock is reclaim tainted which makes sg_alloc_table_from_pages_segment() unusable, since it internally allocates memory. Instead build the sg-table manually. For the non-iommu case this might lead to fewer coalesces, but if that's a problem it can be fixed up later in the resource cursor code. For the iommu case, the whole sg-table may still be coalesced to a single contigous device va region. This avoids marking pages that we don't own dirty and accessed, and it also avoid dereferencing struct pages that we don't own. v2: - Use assert to check whether hmm pfns are valid (Matthew Auld) - Take into account that large pages may cross range boundaries (Matthew Auld) v3: - Don't unnecessarily check for a non-freed sg-table. (Matthew Auld) - Add a missing up_read() in an error path. (Matthew Auld) (cherry picked from commit ea3e66d280ce2576664a862693d1da8fd324c317)
CVE-2025-21938 1 Linux 1 Linux Kernel 2026-06-17 N/A 4.7 MEDIUM
In the Linux kernel, the following vulnerability has been resolved: mptcp: fix 'scheduling while atomic' in mptcp_pm_nl_append_new_local_addr If multiple connection requests attempt to create an implicit mptcp endpoint in parallel, more than one caller may end up in mptcp_pm_nl_append_new_local_addr because none found the address in local_addr_list during their call to mptcp_pm_nl_get_local_id. In this case, the concurrent new_local_addr calls may delete the address entry created by the previous caller. These deletes use synchronize_rcu, but this is not permitted in some of the contexts where this function may be called. During packet recv, the caller may be in a rcu read critical section and have preemption disabled. An example stack: BUG: scheduling while atomic: swapper/2/0/0x00000302 Call Trace: <IRQ> dump_stack_lvl (lib/dump_stack.c:117 (discriminator 1)) dump_stack (lib/dump_stack.c:124) __schedule_bug (kernel/sched/core.c:5943) schedule_debug.constprop.0 (arch/x86/include/asm/preempt.h:33 kernel/sched/core.c:5970) __schedule (arch/x86/include/asm/jump_label.h:27 include/linux/jump_label.h:207 kernel/sched/features.h:29 kernel/sched/core.c:6621) schedule (arch/x86/include/asm/preempt.h:84 kernel/sched/core.c:6804 kernel/sched/core.c:6818) schedule_timeout (kernel/time/timer.c:2160) wait_for_completion (kernel/sched/completion.c:96 kernel/sched/completion.c:116 kernel/sched/completion.c:127 kernel/sched/completion.c:148) __wait_rcu_gp (include/linux/rcupdate.h:311 kernel/rcu/update.c:444) synchronize_rcu (kernel/rcu/tree.c:3609) mptcp_pm_nl_append_new_local_addr (net/mptcp/pm_netlink.c:966 net/mptcp/pm_netlink.c:1061) mptcp_pm_nl_get_local_id (net/mptcp/pm_netlink.c:1164) mptcp_pm_get_local_id (net/mptcp/pm.c:420) subflow_check_req (net/mptcp/subflow.c:98 net/mptcp/subflow.c:213) subflow_v4_route_req (net/mptcp/subflow.c:305) tcp_conn_request (net/ipv4/tcp_input.c:7216) subflow_v4_conn_request (net/mptcp/subflow.c:651) tcp_rcv_state_process (net/ipv4/tcp_input.c:6709) tcp_v4_do_rcv (net/ipv4/tcp_ipv4.c:1934) tcp_v4_rcv (net/ipv4/tcp_ipv4.c:2334) ip_protocol_deliver_rcu (net/ipv4/ip_input.c:205 (discriminator 1)) ip_local_deliver_finish (include/linux/rcupdate.h:813 net/ipv4/ip_input.c:234) ip_local_deliver (include/linux/netfilter.h:314 include/linux/netfilter.h:308 net/ipv4/ip_input.c:254) ip_sublist_rcv_finish (include/net/dst.h:461 net/ipv4/ip_input.c:580) ip_sublist_rcv (net/ipv4/ip_input.c:640) ip_list_rcv (net/ipv4/ip_input.c:675) __netif_receive_skb_list_core (net/core/dev.c:5583 net/core/dev.c:5631) netif_receive_skb_list_internal (net/core/dev.c:5685 net/core/dev.c:5774) napi_complete_done (include/linux/list.h:37 include/net/gro.h:449 include/net/gro.h:444 net/core/dev.c:6114) igb_poll (drivers/net/ethernet/intel/igb/igb_main.c:8244) igb __napi_poll (net/core/dev.c:6582) net_rx_action (net/core/dev.c:6653 net/core/dev.c:6787) handle_softirqs (kernel/softirq.c:553) __irq_exit_rcu (kernel/softirq.c:588 kernel/softirq.c:427 kernel/softirq.c:636) irq_exit_rcu (kernel/softirq.c:651) common_interrupt (arch/x86/kernel/irq.c:247 (discriminator 14)) </IRQ> This problem seems particularly prevalent if the user advertises an endpoint that has a different external vs internal address. In the case where the external address is advertised and multiple connections already exist, multiple subflow SYNs arrive in parallel which tends to trigger the race during creation of the first local_addr_list entries which have the internal address instead. Fix by skipping the replacement of an existing implicit local address if called via mptcp_pm_nl_get_local_id.
CVE-2025-21937 1 Linux 1 Linux Kernel 2026-06-17 N/A 5.5 MEDIUM
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: Add check for mgmt_alloc_skb() in mgmt_remote_name() Add check for the return value of mgmt_alloc_skb() in mgmt_remote_name() to prevent null pointer dereference.
CVE-2025-21936 1 Linux 1 Linux Kernel 2026-06-17 N/A 5.5 MEDIUM
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: Add check for mgmt_alloc_skb() in mgmt_device_connected() Add check for the return value of mgmt_alloc_skb() in mgmt_device_connected() to prevent null pointer dereference.
CVE-2025-21935 1 Linux 1 Linux Kernel 2026-06-17 N/A 5.5 MEDIUM
In the Linux kernel, the following vulnerability has been resolved: rapidio: add check for rio_add_net() in rio_scan_alloc_net() The return value of rio_add_net() should be checked. If it fails, put_device() should be called to free the memory and give up the reference initialized in rio_add_net().
CVE-2025-21934 1 Linux 1 Linux Kernel 2026-06-17 N/A 7.8 HIGH
In the Linux kernel, the following vulnerability has been resolved: rapidio: fix an API misues when rio_add_net() fails rio_add_net() calls device_register() and fails when device_register() fails. Thus, put_device() should be used rather than kfree(). Add "mport->net = NULL;" to avoid a use after free issue.
CVE-2025-21933 1 Linux 1 Linux Kernel 2026-06-17 N/A 5.5 MEDIUM
In the Linux kernel, the following vulnerability has been resolved: arm: pgtable: fix NULL pointer dereference issue When update_mmu_cache_range() is called by update_mmu_cache(), the vmf parameter is NULL, which will cause a NULL pointer dereference issue in adjust_pte(): Unable to handle kernel NULL pointer dereference at virtual address 00000030 when read Hardware name: Atmel AT91SAM9 PC is at update_mmu_cache_range+0x1e0/0x278 LR is at pte_offset_map_rw_nolock+0x18/0x2c Call trace: update_mmu_cache_range from remove_migration_pte+0x29c/0x2ec remove_migration_pte from rmap_walk_file+0xcc/0x130 rmap_walk_file from remove_migration_ptes+0x90/0xa4 remove_migration_ptes from migrate_pages_batch+0x6d4/0x858 migrate_pages_batch from migrate_pages+0x188/0x488 migrate_pages from compact_zone+0x56c/0x954 compact_zone from compact_node+0x90/0xf0 compact_node from kcompactd+0x1d4/0x204 kcompactd from kthread+0x120/0x12c kthread from ret_from_fork+0x14/0x38 Exception stack(0xc0d8bfb0 to 0xc0d8bff8) To fix it, do not rely on whether 'ptl' is equal to decide whether to hold the pte lock, but decide it by whether CONFIG_SPLIT_PTE_PTLOCKS is enabled. In addition, if two vmas map to the same PTE page, there is no need to hold the pte lock again, otherwise a deadlock will occur. Just add the need_lock parameter to let adjust_pte() know this information.
CVE-2025-21932 1 Linux 1 Linux Kernel 2026-06-17 N/A 5.5 MEDIUM
In the Linux kernel, the following vulnerability has been resolved: mm: abort vma_modify() on merge out of memory failure The remainder of vma_modify() relies upon the vmg state remaining pristine after a merge attempt. Usually this is the case, however in the one edge case scenario of a merge attempt failing not due to the specified range being unmergeable, but rather due to an out of memory error arising when attempting to commit the merge, this assumption becomes untrue. This results in vmg->start, end being modified, and thus the proceeding attempts to split the VMA will be done with invalid start/end values. Thankfully, it is likely practically impossible for us to hit this in reality, as it would require a maple tree node pre-allocation failure that would likely never happen due to it being 'too small to fail', i.e. the kernel would simply keep retrying reclaim until it succeeded. However, this scenario remains theoretically possible, and what we are doing here is wrong so we must correct it. The safest option is, when this scenario occurs, to simply give up the operation. If we cannot allocate memory to merge, then we cannot allocate memory to split either (perhaps moreso!). Any scenario where this would be happening would be under very extreme (likely fatal) memory pressure, so it's best we give up early. So there is no doubt it is appropriate to simply bail out in this scenario. However, in general we must if at all possible never assume VMG state is stable after a merge attempt, since merge operations update VMG fields. As a result, additionally also make this clear by storing start, end in local variables. The issue was reported originally by syzkaller, and by Brad Spengler (via an off-list discussion), and in both instances it manifested as a triggering of the assert: VM_WARN_ON_VMG(start >= end, vmg); In vma_merge_existing_range(). It seems at least one scenario in which this is occurring is one in which the merge being attempted is due to an madvise() across multiple VMAs which looks like this: start end |<------>| |----------|------| | vma | next | |----------|------| When madvise_walk_vmas() is invoked, we first find vma in the above (determining prev to be equal to vma as we are offset into vma), and then enter the loop. We determine the end of vma that forms part of the range we are madvise()'ing by setting 'tmp' to this value: /* Here vma->vm_start <= start < (end|vma->vm_end) */ tmp = vma->vm_end; We then invoke the madvise() operation via visit(), letting prev get updated to point to vma as part of the operation: /* Here vma->vm_start <= start < tmp <= (end|vma->vm_end). */ error = visit(vma, &prev, start, tmp, arg); Where the visit() function pointer in this instance is madvise_vma_behavior(). As observed in syzkaller reports, it is ultimately madvise_update_vma() that is invoked, calling vma_modify_flags_name() and vma_modify() in turn. Then, in vma_modify(), we attempt the merge: merged = vma_merge_existing_range(vmg); if (merged) return merged; We invoke this with vmg->start, end set to start, tmp as such: start tmp |<--->| |----------|------| | vma | next | |----------|------| We find ourselves in the merge right scenario, but the one in which we cannot remove the middle (we are offset into vma). Here we have a special case where vmg->start, end get set to perhaps unintuitive values - we intended to shrink the middle VMA and expand the next. This means vmg->start, end are set to... vma->vm_start, start. Now the commit_merge() fails, and vmg->start, end are left like this. This means we return to the rest of vma_modify() with vmg->start, end (here denoted as start', end') set as: start' end' |<-->| |----------|------| | vma | next | |----------|------| So we now erroneously try to split accordingly. This is where the unfortunate ---truncated---
CVE-2025-21931 1 Linux 1 Linux Kernel 2026-06-17 N/A 5.5 MEDIUM
In the Linux kernel, the following vulnerability has been resolved: hwpoison, memory_hotplug: lock folio before unmap hwpoisoned folio Commit b15c87263a69 ("hwpoison, memory_hotplug: allow hwpoisoned pages to be offlined) add page poison checks in do_migrate_range in order to make offline hwpoisoned page possible by introducing isolate_lru_page and try_to_unmap for hwpoisoned page. However folio lock must be held before calling try_to_unmap. Add it to fix this problem. Warning will be produced if folio is not locked during unmap: ------------[ cut here ]------------ kernel BUG at ./include/linux/swapops.h:400! Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP Modules linked in: CPU: 4 UID: 0 PID: 411 Comm: bash Tainted: G W 6.13.0-rc1-00016-g3c434c7ee82a-dirty #41 Tainted: [W]=WARN Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015 pstate: 40400005 (nZcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : try_to_unmap_one+0xb08/0xd3c lr : try_to_unmap_one+0x3dc/0xd3c Call trace: try_to_unmap_one+0xb08/0xd3c (P) try_to_unmap_one+0x3dc/0xd3c (L) rmap_walk_anon+0xdc/0x1f8 rmap_walk+0x3c/0x58 try_to_unmap+0x88/0x90 unmap_poisoned_folio+0x30/0xa8 do_migrate_range+0x4a0/0x568 offline_pages+0x5a4/0x670 memory_block_action+0x17c/0x374 memory_subsys_offline+0x3c/0x78 device_offline+0xa4/0xd0 state_store+0x8c/0xf0 dev_attr_store+0x18/0x2c sysfs_kf_write+0x44/0x54 kernfs_fop_write_iter+0x118/0x1a8 vfs_write+0x3a8/0x4bc ksys_write+0x6c/0xf8 __arm64_sys_write+0x1c/0x28 invoke_syscall+0x44/0x100 el0_svc_common.constprop.0+0x40/0xe0 do_el0_svc+0x1c/0x28 el0_svc+0x30/0xd0 el0t_64_sync_handler+0xc8/0xcc el0t_64_sync+0x198/0x19c Code: f9407be0 b5fff320 d4210000 17ffff97 (d4210000) ---[ end trace 0000000000000000 ]---
CVE-2025-21930 1 Linux 1 Linux Kernel 2026-06-17 N/A 5.5 MEDIUM
In the Linux kernel, the following vulnerability has been resolved: wifi: iwlwifi: mvm: don't try to talk to a dead firmware This fixes: bad state = 0 WARNING: CPU: 10 PID: 702 at drivers/net/wireless/inel/iwlwifi/iwl-trans.c:178 iwl_trans_send_cmd+0xba/0xe0 [iwlwifi] Call Trace: <TASK> ? __warn+0xca/0x1c0 ? iwl_trans_send_cmd+0xba/0xe0 [iwlwifi 64fa9ad799a0e0d2ba53d4af93a53ad9a531f8d4] iwl_fw_dbg_clear_monitor_buf+0xd7/0x110 [iwlwifi 64fa9ad799a0e0d2ba53d4af93a53ad9a531f8d4] _iwl_dbgfs_fw_dbg_clear_write+0xe2/0x120 [iwlmvm 0e8adb18cea92d2c341766bcc10b18699290068a] Ask whether the firmware is alive before sending a command.
CVE-2025-21929 1 Linux 1 Linux Kernel 2026-06-17 N/A 7.8 HIGH
In the Linux kernel, the following vulnerability has been resolved: HID: intel-ish-hid: Fix use-after-free issue in hid_ishtp_cl_remove() During the `rmmod` operation for the `intel_ishtp_hid` driver, a use-after-free issue can occur in the hid_ishtp_cl_remove() function. The function hid_ishtp_cl_deinit() is called before ishtp_hid_remove(), which can lead to accessing freed memory or resources during the removal process. Call Trace: ? ishtp_cl_send+0x168/0x220 [intel_ishtp] ? hid_output_report+0xe3/0x150 [hid] hid_ishtp_set_feature+0xb5/0x120 [intel_ishtp_hid] ishtp_hid_request+0x7b/0xb0 [intel_ishtp_hid] hid_hw_request+0x1f/0x40 [hid] sensor_hub_set_feature+0x11f/0x190 [hid_sensor_hub] _hid_sensor_power_state+0x147/0x1e0 [hid_sensor_trigger] hid_sensor_runtime_resume+0x22/0x30 [hid_sensor_trigger] sensor_hub_remove+0xa8/0xe0 [hid_sensor_hub] hid_device_remove+0x49/0xb0 [hid] hid_destroy_device+0x6f/0x90 [hid] ishtp_hid_remove+0x42/0x70 [intel_ishtp_hid] hid_ishtp_cl_remove+0x6b/0xb0 [intel_ishtp_hid] ishtp_cl_device_remove+0x4a/0x60 [intel_ishtp] ... Additionally, ishtp_hid_remove() is a HID level power off, which should occur before the ISHTP level disconnect. This patch resolves the issue by reordering the calls in hid_ishtp_cl_remove(). The function ishtp_hid_remove() is now called before hid_ishtp_cl_deinit().
CVE-2025-21928 1 Linux 1 Linux Kernel 2026-06-17 N/A 7.8 HIGH
In the Linux kernel, the following vulnerability has been resolved: HID: intel-ish-hid: Fix use-after-free issue in ishtp_hid_remove() The system can experience a random crash a few minutes after the driver is removed. This issue occurs due to improper handling of memory freeing in the ishtp_hid_remove() function. The function currently frees the `driver_data` directly within the loop that destroys the HID devices, which can lead to accessing freed memory. Specifically, `hid_destroy_device()` uses `driver_data` when it calls `hid_ishtp_set_feature()` to power off the sensor, so freeing `driver_data` beforehand can result in accessing invalid memory. This patch resolves the issue by storing the `driver_data` in a temporary variable before calling `hid_destroy_device()`, and then freeing the `driver_data` after the device is destroyed.
CVE-2025-21927 1 Linux 1 Linux Kernel 2026-06-17 N/A 7.8 HIGH
In the Linux kernel, the following vulnerability has been resolved: nvme-tcp: fix potential memory corruption in nvme_tcp_recv_pdu() nvme_tcp_recv_pdu() doesn't check the validity of the header length. When header digests are enabled, a target might send a packet with an invalid header length (e.g. 255), causing nvme_tcp_verify_hdgst() to access memory outside the allocated area and cause memory corruptions by overwriting it with the calculated digest. Fix this by rejecting packets with an unexpected header length.
CVE-2025-21926 1 Linux 1 Linux Kernel 2026-06-17 N/A 5.5 MEDIUM
In the Linux kernel, the following vulnerability has been resolved: net: gso: fix ownership in __udp_gso_segment In __udp_gso_segment the skb destructor is removed before segmenting the skb but the socket reference is kept as-is. This is an issue if the original skb is later orphaned as we can hit the following bug: kernel BUG at ./include/linux/skbuff.h:3312! (skb_orphan) RIP: 0010:ip_rcv_core+0x8b2/0xca0 Call Trace: ip_rcv+0xab/0x6e0 __netif_receive_skb_one_core+0x168/0x1b0 process_backlog+0x384/0x1100 __napi_poll.constprop.0+0xa1/0x370 net_rx_action+0x925/0xe50 The above can happen following a sequence of events when using OpenVSwitch, when an OVS_ACTION_ATTR_USERSPACE action precedes an OVS_ACTION_ATTR_OUTPUT action: 1. OVS_ACTION_ATTR_USERSPACE is handled (in do_execute_actions): the skb goes through queue_gso_packets and then __udp_gso_segment, where its destructor is removed. 2. The segments' data are copied and sent to userspace. 3. OVS_ACTION_ATTR_OUTPUT is handled (in do_execute_actions) and the same original skb is sent to its path. 4. If it later hits skb_orphan, we hit the bug. Fix this by also removing the reference to the socket in __udp_gso_segment.
CVE-2025-21925 1 Linux 1 Linux Kernel 2026-06-17 N/A 5.5 MEDIUM
In the Linux kernel, the following vulnerability has been resolved: llc: do not use skb_get() before dev_queue_xmit() syzbot is able to crash hosts [1], using llc and devices not supporting IFF_TX_SKB_SHARING. In this case, e1000 driver calls eth_skb_pad(), while the skb is shared. Simply replace skb_get() by skb_clone() in net/llc/llc_s_ac.c Note that e1000 driver might have an issue with pktgen, because it does not clear IFF_TX_SKB_SHARING, this is an orthogonal change. We need to audit other skb_get() uses in net/llc. [1] kernel BUG at net/core/skbuff.c:2178 ! Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI CPU: 0 UID: 0 PID: 16371 Comm: syz.2.2764 Not tainted 6.14.0-rc4-syzkaller-00052-gac9c34d1e45a #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:pskb_expand_head+0x6ce/0x1240 net/core/skbuff.c:2178 Call Trace: <TASK> __skb_pad+0x18a/0x610 net/core/skbuff.c:2466 __skb_put_padto include/linux/skbuff.h:3843 [inline] skb_put_padto include/linux/skbuff.h:3862 [inline] eth_skb_pad include/linux/etherdevice.h:656 [inline] e1000_xmit_frame+0x2d99/0x5800 drivers/net/ethernet/intel/e1000/e1000_main.c:3128 __netdev_start_xmit include/linux/netdevice.h:5151 [inline] netdev_start_xmit include/linux/netdevice.h:5160 [inline] xmit_one net/core/dev.c:3806 [inline] dev_hard_start_xmit+0x9a/0x7b0 net/core/dev.c:3822 sch_direct_xmit+0x1ae/0xc30 net/sched/sch_generic.c:343 __dev_xmit_skb net/core/dev.c:4045 [inline] __dev_queue_xmit+0x13d4/0x43e0 net/core/dev.c:4621 dev_queue_xmit include/linux/netdevice.h:3313 [inline] llc_sap_action_send_test_c+0x268/0x320 net/llc/llc_s_ac.c:144 llc_exec_sap_trans_actions net/llc/llc_sap.c:153 [inline] llc_sap_next_state net/llc/llc_sap.c:182 [inline] llc_sap_state_process+0x239/0x510 net/llc/llc_sap.c:209 llc_ui_sendmsg+0xd0d/0x14e0 net/llc/af_llc.c:993 sock_sendmsg_nosec net/socket.c:718 [inline]
CVE-2025-21924 1 Linux 1 Linux Kernel 2026-06-17 N/A 5.5 MEDIUM
In the Linux kernel, the following vulnerability has been resolved: net: hns3: make sure ptp clock is unregister and freed if hclge_ptp_get_cycle returns an error During the initialization of ptp, hclge_ptp_get_cycle might return an error and returned directly without unregister clock and free it. To avoid that, call hclge_ptp_destroy_clock to unregist and free clock if hclge_ptp_get_cycle failed.
CVE-2025-21923 1 Linux 1 Linux Kernel 2026-06-17 N/A 7.8 HIGH
In the Linux kernel, the following vulnerability has been resolved: HID: hid-steam: Fix use-after-free when detaching device When a hid-steam device is removed it must clean up the client_hdev used for intercepting hidraw access. This can lead to scheduling deferred work to reattach the input device. Though the cleanup cancels the deferred work, this was done before the client_hdev itself is cleaned up, so it gets rescheduled. This patch fixes the ordering to make sure the deferred work is properly canceled.
CVE-2025-21922 1 Linux 1 Linux Kernel 2026-06-17 N/A 5.5 MEDIUM
In the Linux kernel, the following vulnerability has been resolved: ppp: Fix KMSAN uninit-value warning with bpf Syzbot caught an "KMSAN: uninit-value" warning [1], which is caused by the ppp driver not initializing a 2-byte header when using socket filter. The following code can generate a PPP filter BPF program: ''' struct bpf_program fp; pcap_t *handle; handle = pcap_open_dead(DLT_PPP_PPPD, 65535); pcap_compile(handle, &fp, "ip and outbound", 0, 0); bpf_dump(&fp, 1); ''' Its output is: ''' (000) ldh [2] (001) jeq #0x21 jt 2 jf 5 (002) ldb [0] (003) jeq #0x1 jt 4 jf 5 (004) ret #65535 (005) ret #0 ''' Wen can find similar code at the following link: https://github.com/ppp-project/ppp/blob/master/pppd/options.c#L1680 The maintainer of this code repository is also the original maintainer of the ppp driver. As you can see the BPF program skips 2 bytes of data and then reads the 'Protocol' field to determine if it's an IP packet. Then it read the first byte of the first 2 bytes to determine the direction. The issue is that only the first byte indicating direction is initialized in current ppp driver code while the second byte is not initialized. For normal BPF programs generated by libpcap, uninitialized data won't be used, so it's not a problem. However, for carefully crafted BPF programs, such as those generated by syzkaller [2], which start reading from offset 0, the uninitialized data will be used and caught by KMSAN. [1] https://syzkaller.appspot.com/bug?extid=853242d9c9917165d791 [2] https://syzkaller.appspot.com/text?tag=ReproC&x=11994913980000
CVE-2025-21921 1 Linux 1 Linux Kernel 2026-06-17 N/A 5.5 MEDIUM
In the Linux kernel, the following vulnerability has been resolved: net: ethtool: netlink: Allow NULL nlattrs when getting a phy_device ethnl_req_get_phydev() is used to lookup a phy_device, in the case an ethtool netlink command targets a specific phydev within a netdev's topology. It takes as a parameter a const struct nlattr *header that's used for error handling : if (!phydev) { NL_SET_ERR_MSG_ATTR(extack, header, "no phy matching phyindex"); return ERR_PTR(-ENODEV); } In the notify path after a ->set operation however, there's no request attributes available. The typical callsite for the above function looks like: phydev = ethnl_req_get_phydev(req_base, tb[ETHTOOL_A_XXX_HEADER], info->extack); So, when tb is NULL (such as in the ethnl notify path), we have a nice crash. It turns out that there's only the PLCA command that is in that case, as the other phydev-specific commands don't have a notification. This commit fixes the crash by passing the cmd index and the nlattr array separately, allowing NULL-checking it directly inside the helper.