What’s Vulnerable › Vulnerabilities
CVE-2026-80844: xfrm: ah6: validate routing header segments_left
- Severity: unknown
- 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: 2026-09-04 · updated 2026-10-19
Description
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 kernel: 2.6.12 — fixed in 7.3
How to fix
Upgrade to a fixed version: Linux kernel 7.3. Check the vendor advisory for mitigations.
In the news
References
- https://git.kernel.org/stable/c/0bf11081ad3753938a2b48723ce6298dbac743a1
- https://git.kernel.org/stable/c/1516e31ac458a738be485620579d8f7fb2700fcb
- https://git.kernel.org/stable/c/1b7e066eabcc7d6d8f476c34739b45932f2f4c31
- https://git.kernel.org/stable/c/2dc650956e4e163b879b3fb1027f9557abc5c985
- https://git.kernel.org/stable/c/46640c814f25f096b0b0045ca50e1b7030cd8a30
- https://git.kernel.org/stable/c/48b0e36cf54358276ee7aa897034c973097d2bc9
- https://git.kernel.org/stable/c/6733ae71268a27d598cfb3f3339a3c950b9b656d
- https://git.kernel.org/stable/c/7bad4bda74dc4713f398d3b7624ff05478e3a568
- https://git.kernel.org/stable/c/f00df8500e5a36ba70d336fd34bd2152ea074e5f
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