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)`.

References

https://git.kernel.org/stable/c/fdce0b3590f724540795b874b4c8850c90e6b0a8

https://git.kernel.org/stable/c/9eda5478746ef7dc0e4e537b5a5e4b0ca1027091

https://git.kernel.org/stable/c/807d6ee15804df6f01a35c910f09612e858739a6

https://git.kernel.org/stable/c/309ae3e9a51a69699ca94eac5fac5688fa562d55

https://git.kernel.org/stable/c/288138418bef956f8b295751a4536c60f0e89f4a

Details

Source: Mitre, NVD

Published: 2026-04-25

Updated: 2026-05-06

Risk Information

CVSS v2

Base Score: 9.7

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:P/A:C

Severity: High

CVSS v3

Base Score: 9.4

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H

Severity: Critical

EPSS

EPSS: 0.00018