In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_log: validate MAC header was set before dumping it
The fallback path of dump_mac_header() guards the MAC header access
only with "skb->mac_header != skb->network_header", without checking
skb_mac_header_was_set(). When the MAC header is unset, mac_header is
0xffff, so the test passes and skb_mac_header(skb) returns
skb->head + 0xffff, ~64 KiB past the buffer; the loop then reads
dev->hard_header_len bytes out of bounds into the kernel log.
This is reachable via the netdev logger: nf_log_unknown_packet() calls
dump_mac_header() unconditionally, and an skb sent through AF_PACKET
with PACKET_QDISC_BYPASS reaches the egress hook with mac_header still
unset (__dev_queue_xmit(), which would reset it, is bypassed).
Add the skb_mac_header_was_set() check the ARPHRD_ETHER path already
uses, and replace the open-coded MAC header length test with
skb_mac_header_len(). Only skbs with an unset MAC header are affected;
valid ones are dumped as before.
BUG: KASAN: slab-out-of-bounds in dump_mac_header (net/netfilter/nf_log_syslog.c:831)
Read of size 1 at addr ffff88800ea49d3f by task exploit/148
Call Trace:
kasan_report (mm/kasan/report.c:595)
dump_mac_header (net/netfilter/nf_log_syslog.c:831)
nf_log_netdev_packet (net/netfilter/nf_log_syslog.c:938 net/netfilter/nf_log_syslog.c:963)
nf_log_packet (net/netfilter/nf_log.c:260)
nft_log_eval (net/netfilter/nft_log.c:60)
nft_do_chain (net/netfilter/nf_tables_core.c:285)
nft_do_chain_netdev (net/netfilter/nft_chain_filter.c:307)
nf_hook_slow (net/netfilter/core.c:619)
nf_hook_direct_egress (net/packet/af_packet.c:257)
packet_xmit (net/packet/af_packet.c:280)
packet_sendmsg (net/packet/af_packet.c:3114)
__sys_sendto (net/socket.c:2265)
References
Configurations
Configuration 1 (hide)
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History
24 Jul 2026, 15:17
| Type | Values Removed | Values Added |
|---|---|---|
| References |
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08 Jul 2026, 19:08
| Type | Values Removed | Values Added |
|---|---|---|
| CPE | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.1:rc7:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.1:rc6:*:*:*:*:*:* |
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| First Time |
Linux linux Kernel
Linux |
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| References | () https://git.kernel.org/stable/c/65ef7397eb9a296e91839f5fd10be96f23d332e7 - Patch | |
| References | () https://git.kernel.org/stable/c/8a81e336da685423f5b64aac4d571e63d674c52a - Patch | |
| References | () https://git.kernel.org/stable/c/a84b6fedbc97078788be78dbdd7517d143ad1a77 - Patch | |
| References | () https://git.kernel.org/stable/c/af1b7699466f6556b351fa25d3dc870abfb5d310 - Patch | |
| References | () https://git.kernel.org/stable/c/befb8968a2abdfa948d5600ea7f7a509a292a590 - Patch | |
| References | () https://git.kernel.org/stable/c/c38d41134085193efd5b237cf513ad5b3421a60d - Patch | |
| References | () https://git.kernel.org/stable/c/d704ee9c7bc68a161684c51a7ac05b446dcf38d4 - Patch | |
| CWE | CWE-125 |
28 Jun 2026, 08:16
| Type | Values Removed | Values Added |
|---|---|---|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 7.1 |
24 Jun 2026, 08:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-06-24 08:16
Updated : 2026-07-24 15:17
NVD link : CVE-2026-52942
Mitre link : CVE-2026-52942
CVE.ORG link : CVE-2026-52942
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-125
Out-of-bounds Read