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VulnerabilityPublished Updated

CVE-2026-52942: Linux kernel · Out-of-bounds Read

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.1 High · fixed in d704ee9c7bc68a161684c51a7ac05b446dcf38d4 : patch Linux kernel soon.

Data as of 26 Oct 2026, 12:55 UTC

CVSS 3.1 base score
7.1High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in d704ee9c7bc68a161684c51a7ac05b446dcf38d4, c38d41134085193efd5b237cf513ad5b3421a60d, befb8968a2abdfa948d5600ea7f7a509a292a590 +5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 24 Jun 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 7eb9282cd0efac08b8377cbd5037ba297c77e3f7, < d704ee9c7bc68a161684c51a7ac05b446dcf38d4
Fixed in
  • d704ee9c7bc68a161684c51a7ac05b446dcf38d4
LinuxLinuxAffected
  • ≥ 7eb9282cd0efac08b8377cbd5037ba297c77e3f7, < c38d41134085193efd5b237cf513ad5b3421a60d
Fixed in
  • c38d41134085193efd5b237cf513ad5b3421a60d
LinuxLinuxAffected
  • ≥ 7eb9282cd0efac08b8377cbd5037ba297c77e3f7, < befb8968a2abdfa948d5600ea7f7a509a292a590
Fixed in
  • befb8968a2abdfa948d5600ea7f7a509a292a590
LinuxLinuxAffected
  • ≥ 7eb9282cd0efac08b8377cbd5037ba297c77e3f7, < af1b7699466f6556b351fa25d3dc870abfb5d310
Fixed in
  • af1b7699466f6556b351fa25d3dc870abfb5d310
LinuxLinuxAffected
  • ≥ 7eb9282cd0efac08b8377cbd5037ba297c77e3f7, < a84b6fedbc97078788be78dbdd7517d143ad1a77
Fixed in
  • a84b6fedbc97078788be78dbdd7517d143ad1a77
LinuxLinuxAffected
  • ≥ 7eb9282cd0efac08b8377cbd5037ba297c77e3f7, < 65ef7397eb9a296e91839f5fd10be96f23d332e7
Fixed in
  • 65ef7397eb9a296e91839f5fd10be96f23d332e7

Description

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

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