# CVE-2026-80844 — Linux

> As of 2026-09-04, CVE-2026-80844 is a vulnerability in Linux, EPSS 0.4% (34.9th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-80844, most recently “"LPE Quartet": Public Exploits Released for Four Linux Kernel Local-Root Flaws (DirtyAH6, TUNderflow, PPPoEject, DiagSpill)”.

**Last updated:** 2026-09-04

## What is CVE-2026-80844?

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.

1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 31 days ago.

## Severity and exploitation probability

- **EPSS (FIRST):** 0.4% probability of exploitation in the next 30 days, higher than 34.9% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 3.4/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-09-04

## Is CVE-2026-80844 being exploited?

Weaponised exploit code for CVE-2026-80844 is publicly available. 2 public proof-of-concept repositories are tracked for this identifier.

- [0xBlackash/CVE-2026-80844](https://github.com/0xBlackash/CVE-2026-80844) (github)
- [HORKimhab/CVE-2026-80844](https://github.com/HORKimhab/CVE-2026-80844) (github)

## Affected products and versions

- [Linux](https://intel.threadlinqs.com/vendors/linux): Linux

## How to fix CVE-2026-80844

No vendor patch reference has been recorded for CVE-2026-80844 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-80844

1 tracked threat in the Threadlinqs corpus references CVE-2026-80844, either in the campaign’s CVE list or as an indicator on the campaign record.

- ["LPE Quartet": Public Exploits Released for Four Linux Kernel Local-Root Flaws (DirtyAH6, TUNderflow, PPPoEject, DiagSpill)](https://intel.threadlinqs.com/threat/TL-2026-2572) — HIGH · 2026-09-18

## Sources

Enriched from CVE.org, NVD, FIRST EPSS, public proof-of-concept repositories. Last verified by Threadlinqs on 2026-09-24. This product uses the NVD API but is not endorsed or certified by the NVD.

**Other references**

- [git.kernel.org](https://git.kernel.org/stable/c/2dc650956e4e163b879b3fb1027f9557abc5c985)
- [git.kernel.org (48b0e36cf54358276ee7aa897034c973097d2bc9)](https://git.kernel.org/stable/c/48b0e36cf54358276ee7aa897034c973097d2bc9)
- [git.kernel.org (1b7e066eabcc7d6d8f476c34739b45932f2f4c31)](https://git.kernel.org/stable/c/1b7e066eabcc7d6d8f476c34739b45932f2f4c31)
- [git.kernel.org (f00df8500e5a36ba70d336fd34bd2152ea074e5f)](https://git.kernel.org/stable/c/f00df8500e5a36ba70d336fd34bd2152ea074e5f)
- [git.kernel.org (1516e31ac458a738be485620579d8f7fb2700fcb)](https://git.kernel.org/stable/c/1516e31ac458a738be485620579d8f7fb2700fcb)

_Showing 5 of 9 recorded references._

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-80844
Full detection coverage and IOCs for threats exploiting CVE-2026-80844 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp