CVE-2026-31685

Critical

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: ip6t_eui64: reject invalid MAC header for all packets `eui64_mt6()` derives a modified EUI-64 from the Ethernet source address and compares it with the low 64 bits of the IPv6 source address. The existing guard only rejects an invalid MAC header when `par->fragoff != 0`. For packets with `par->fragoff == 0`, `eui64_mt6()` can still reach `eth_hdr(skb)` even when the MAC header is not valid. Fix this by removing the `par->fragoff != 0` condition so that packets with an invalid MAC header are rejected before accessing `eth_hdr(skb)`.

SeverityCritical
CVSS9.4
Exploit probability—
ProductLinux Kernel
PublishedApr 25, 2026
First seenApr 25, 2026

How to fix

Update
  • linux linux_kernel6.6.136, 6.12.83, 6.18.24, 6.19.14 or later

Affected products

ProductAffected versionsFixed in
linux linux_kernel2.6.12.1 ≤ v < 6.6.136, 6.7 ≤ v < 6.12.83, 6.13 ≤ v < 6.18.24, 6.19 ≤ v < 6.19.14, 2.6.12, 7.06.6.136, 6.12.83, 6.18.24, 6.19.14

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