In the Linux kernel, the following vulnerability has been resolved:
openvswitch: cap upcall PID array size and pre-size vport replies
The vport netlink reply helpers allocate a fixed-size skb with
nlmsg_new(NLMSG_DEFAULT_SIZE, ...) but serialize the full upcall PID
array via ovs_vport_get_upcall_portids(). Since
ovs_vport_set_upcall_portids() accepts any non-zero multiple of
sizeof(u32) with no upper bound, a CAP_NET_ADMIN user can install a PID
array large enough to overflow the reply buffer, causing nla_put() to
fail with -EMSGSIZE and hitting BUG_ON(err < 0). On systems with
unprivileged user namespaces enabled (e.g., Ubuntu default), this is
reachable via unshare -Urn since OVS vport mutation operations use
GENL_UNS_ADMIN_PERM.
kernel BUG at net/openvswitch/datapath.c:2414!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 1 UID: 0 PID: 65 Comm: poc Not tainted 7.0.0-rc7-00195-geb216e422044 #1
RIP: 0010:ovs_vport_cmd_set+0x34c/0x400
Call Trace:
<TASK>
genl_family_rcv_msg_doit (net/netlink/genetlink.c:1116)
genl_rcv_msg (net/netlink/genetlink.c:1194)
netlink_rcv_skb (net/netlink/af_netlink.c:2550)
genl_rcv (net/netlink/genetlink.c:1219)
netlink_unicast (net/netlink/af_netlink.c:1344)
netlink_sendmsg (net/netlink/af_netlink.c:1894)
__sys_sendto (net/socket.c:2206)
__x64_sys_sendto (net/socket.c:2209)
do_syscall_64 (arch/x86/entry/syscall_64.c:63)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
</TASK>
Kernel panic - not syncing: Fatal exception
Reject attempts to set more PIDs than nr_cpu_ids in
ovs_vport_set_upcall_portids(), and pre-compute the worst-case reply
size in ovs_vport_cmd_msg_size() based on that bound, similar to the
existing ovs_dp_cmd_msg_size(). nr_cpu_ids matches the cap already
used by the per-CPU dispatch configuration on the datapath side
(ovs_dp_cmd_fill_info() serialises at most nr_cpu_ids PIDs), so the
two sides stay consistent.
References
Configurations
Configuration 1 (hide)
|
History
26 Jun 2026, 18:56
| Type | Values Removed | Values Added |
|---|---|---|
| CPE | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| First Time |
Linux linux Kernel
Linux |
|
| References | () https://git.kernel.org/stable/c/1d6c02b86329883aa467a3a61f8d34369db73a2f - Patch | |
| References | () https://git.kernel.org/stable/c/2091c6aa0df6aba47deb5c8ab232b1cb60af3519 - Patch | |
| References | () https://git.kernel.org/stable/c/8d59b80e69dddb665eb2de36e62859ab2073470e - Patch | |
| References | () https://git.kernel.org/stable/c/b39f763d720d623218bc1d95ace6855d7b474e81 - Patch | |
| References | () https://git.kernel.org/stable/c/d9e47e29aacb9f8a9d59feb6ab5b128a9bbb40b0 - Patch | |
| References | () https://git.kernel.org/stable/c/f99ac36b5d7c719d08a69fcdecce40f78a874e15 - Patch | |
| References | () https://git.kernel.org/stable/c/f9ef3db77a383d66847fd082c2b437d8ae4d9c63 - Patch | |
| References | () https://git.kernel.org/stable/c/fa6e90bc443bed8dc0d55bc5ea5b27ffdfe37704 - Patch | |
| CWE | NVD-CWE-noinfo | |
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 5.5 |
01 Jun 2026, 17:17
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
27 May 2026, 11:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-05-27 11:16
Updated : 2026-06-26 18:56
NVD link : CVE-2026-45840
Mitre link : CVE-2026-45840
CVE.ORG link : CVE-2026-45840
JSON object : View
Products Affected
linux
- linux_kernel
CWE