CVE-2026-80844: Linux

EPSS: 0.4% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: xfrm: ah6: validate routing header segments_left AH6 rearranges routing-header addresses before computing or verifying the ICV. ipv6_rearrange_rthdr() assumes that segments_left is not larger than the number of addresses described by the routing header's hdrlen field. That assumption does not hold for raw IPv6 HDRINCL packets. A packet with hdrlen equal to 2 describes one address, but can carry an arbitrary segments_left value. With segments_left equal to 255, the function moves its address pointer 4,064 bytes backwards and passes a 4,064-byte length to memmove(), resulting in an out-of-bounds access. Validate the invariant locally before modifying the routing header or performing any address-pointer arithmetic, and propagate malformed-header errors to the existing AH6 input and output error paths.

Affected products

• Linux Linux: from 2.6.12, before 5.10.269 (fixed in 5.10.269); from 5.11, before 5.15.220 (fixed in 5.15.220); from 5.16, before 6.1.187 (fixed in 6.1.187); from 6.2, before 6.6.156 (fixed in 6.6.156); from 6.7, before 6.12.108 (fixed in 6.12.108); from 6.13, before 6.18.49 (fixed in 6.18.49); …

Published 2026-09-04. Last modified 2026-09-04.