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.

Metrics

No CVSS v4.0

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

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Fixes

Solution

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Workaround

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References
Link Providers
https://git.kernel.org/stable/c/0bf11081ad3753938a2b48723ce6298dbac743a1 cve-icon cve-icon
https://git.kernel.org/stable/c/1516e31ac458a738be485620579d8f7fb2700fcb cve-icon cve-icon
https://git.kernel.org/stable/c/1b7e066eabcc7d6d8f476c34739b45932f2f4c31 cve-icon cve-icon
https://git.kernel.org/stable/c/2dc650956e4e163b879b3fb1027f9557abc5c985 cve-icon cve-icon
https://git.kernel.org/stable/c/46640c814f25f096b0b0045ca50e1b7030cd8a30 cve-icon cve-icon
https://git.kernel.org/stable/c/48b0e36cf54358276ee7aa897034c973097d2bc9 cve-icon cve-icon
https://git.kernel.org/stable/c/6733ae71268a27d598cfb3f3339a3c950b9b656d cve-icon cve-icon
https://git.kernel.org/stable/c/7bad4bda74dc4713f398d3b7624ff05478e3a568 cve-icon cve-icon
https://git.kernel.org/stable/c/f00df8500e5a36ba70d336fd34bd2152ea074e5f cve-icon cve-icon
History

Fri, 04 Sep 2026 19:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-119
CWE-20

Fri, 04 Sep 2026 16:00:00 +0000

Type Values Removed Values Added
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.
Title xfrm: ah6: validate routing header segments_left
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-09-04T15:54:54.295Z

Reserved: 2026-08-26T14:34:25.796Z

Link: CVE-2026-80844

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-04T16:18:13.023

Modified: 2026-09-04T16:18:13.023

Link: CVE-2026-80844

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-04T19:30:04Z

Weaknesses