CVE-2026-53131: netfilter: require Ethernet MAC header before using eth_hdr()

Severity: critical (CVSS 9.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-25 · updated 2026-10-19
Weakness: CWE-125

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: require Ethernet MAC header before using eth_hdr() `ip6t_eui64`, `xt_mac`, the `bitmap:ip,mac`, `hash:ip,mac`, and `hash:mac` ipset types, and `nf_log_syslog` access `eth_hdr(skb)` after either assuming that the skb is associated with an Ethernet device or checking only that the `ETH_HLEN` bytes at `skb_mac_header(skb)` lie between `skb->head` and `skb->data`. Make these paths first verify that the skb is associated with an Ethernet device, that the MAC header was set, and that it spans at least a full Ethernet header before accessing `eth_hdr(skb)`.

Affected products

Linux kernel: from 2.6.12.1 before 5.15.210; from 5.16 before 6.1.176; from 6.2 before 6.6.143; from 6.7 before 6.12.94; from 6.13 before 6.18.36; from 6.19 before 7.0.13 — fixed in 5.15.210, 6.1.176, 6.12.94, 6.18.36, 6.6.143, 7.0.13

How to fix

Upgrade to a fixed version: Linux kernel 5.15.210, 6.1.176, 6.12.94, 6.18.36. Check the vendor advisory for mitigations.

References

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