Unknown

CVE-2026-80844 — xfrm: ah6: validate routing header segments_left

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.

Published Sep 4, 2026 · Updated Oct 19, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: Linux

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.4% (30-day exploitation probability)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.43%

ahead of 37% of scored CVEs · Oct 27, 2026

Affects

Linux

CVSS base

—

Score not published yet.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Linux	Linux	≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 2dc650956e4e163b879b3fb1027f9557abc5c985≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 48b0e36cf54358276ee7aa897034c973097d2bc9≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 1b7e066eabcc7d6d8f476c34739b45932f2f4c31≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < f00df8500e5a36ba70d336fd34bd2152ea074e5f≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 1516e31ac458a738be485620579d8f7fb2700fcb≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 6733ae71268a27d598cfb3f3339a3c950b9b656d≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 0bf11081ad3753938a2b48723ce6298dbac743a1≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 46640c814f25f096b0b0045ca50e1b7030cd8a30 and 2 more ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 7bad4bda74dc4713f398d3b7624ff05478e3a568version 2.6.12	Vulnerable	CVE Program (cve.org) e CISA ADP

EPSS over time FIRST

Oct 15, 2026 → Oct 27, 2026 · 12 reading(s) · max 0.43%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Not enough vector or weakness data: use the affected application’s logs as a starting point.

application logs

Timeline

What happened to this CVE, newest first.

2026
Record published
Oct 15, 2026
Affected products added · linux/linux
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
Source status changed · → Received
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Sep 4, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

1× References added · Oct 19, 2026 – Oct 19, 2026
1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

11 on the record

git.kernel.org/stable/c/1b7e066eabcc7d6d8f476c34739b45932f2f4c31
NIST National Vulnerability Database
git.kernel.org/stable/c/2dc650956e4e163b879b3fb1027f9557abc5c985
NIST National Vulnerability Database
git.kernel.org/stable/c/f00df8500e5a36ba70d336fd34bd2152ea074e5f
NIST National Vulnerability Database
git.kernel.org/stable/c/6733ae71268a27d598cfb3f3339a3c950b9b656d
NIST National Vulnerability Database
nvd.nist.gov/vuln/detail/CVE-2026-80844
GitHub Security Advisories
git.kernel.org/stable/c/7bad4bda74dc4713f398d3b7624ff05478e3a568
NIST National Vulnerability Database
git.kernel.org/stable/c/1516e31ac458a738be485620579d8f7fb2700fcb
NIST National Vulnerability Database
github.com/advisories/GHSA-jv4j-682x-84w7
GitHub Security Advisories
git.kernel.org/stable/c/48b0e36cf54358276ee7aa897034c973097d2bc9
NIST National Vulnerability Database
git.kernel.org/stable/c/0bf11081ad3753938a2b48723ce6298dbac743a1
NIST National Vulnerability Database
git.kernel.org/stable/c/46640c814f25f096b0b0045ca50e1b7030cd8a30
NIST National Vulnerability Database

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

Unknown CVE-2026-99100 wifi: p54: validate firmware record lengths 47m
Unknown CVE-2026-99092 riscv: patch: fix handling of bpf-jit execmem addresses 1d
Unknown CVE-2026-99093 mm: don't schedule deferred kernel page table freeing while booting 1d
Unknown CVE-2026-99095 drm/vc4: drain the hangcheck timer and works on V3D unbind 1d
Unknown CVE-2026-99096 io_uring/register: don't exempt disabled rings from task restrictions 1d
Unknown CVE-2026-99097 tee: shm: reject zero-sized allocations in tee_dyn_shm_alloc_helper() 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No CVSS score published by NVD, the CNA, CISA or GitHub so far.
No fixed version, patch or mitigation documented.
No CISA SSVC assessment.
No CWE classification.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-80844 is "xfrm: ah6: validate routing header segments_left", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. EPSS 0.43% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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