netfilter: conntrack: revert ct extension genid infrastructure (CVE-2026-80636) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-80636

netfilter: conntrack: revert ct extension genid infrastructure

Answer in brief

CVE-2026-80636 records a Unknown severity vulnerability in netfilter: conntrack: revert ct extension genid infrastructure. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 28, 2026Updated Aug 28, 2026Source checked Aug 28, 2026First seen by HOL Aug 28, 2026Material review Aug 28, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=c56716c69ce1ac320432fb1ea5654196ba24d2f8 <6bba4846f196d081bf553391d12b5a73dcc48685 \|\| >=c56716c69ce1ac320432fb1ea5654196ba24d2f8 <61eab1d0237eb513fe73e391a5926ee70092c325 \|\| >=c56716c69ce1ac320432fb1ea5654196ba24d2f8 <d53eecbca16f056abba274075cb15120ab062518 \|\| >=c56716c69ce1ac320432fb1ea5654196ba24d2f8 <a052a94bcc629acaecc2ce42a4af77f8fa399757 \|\| >=c56716c69ce1ac320432fb1ea5654196ba24d2f8 <35e21a4dccc5c255ba59ccfbfeb4629ed21da972	6bba4846f196d081bf553391d12b5a73dcc48685, 61eab1d0237eb513fe73e391a5926ee70092c325, d53eecbca16f056abba274075cb15120ab062518, a052a94bcc629acaecc2ce42a4af77f8fa399757, 35e21a4dccc5c255ba59ccfbfeb4629ed21da972
Linux/Linuxgeneric	5.19	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 6bba4846f196d081bf553391d12b5a73dcc48685 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 28, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 28, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 28, 2026

Sources and claim methodology

Upstream source description

In the Linux kernel, the following vulnerability has been resolved: netfilter: conntrack: revert ct extension genid infrastructure This infrastructure is not used anymore after moving ct timeout and helper to use datapath refcount to track object use. Revert commit c56716c69ce1 ("netfilter: extensions: introduce extension genid count") this patch disables all ct extensions (leading to NULL) for unconfirmed conntracks, when this is only targeted at ct helper and ct timeout. There is also codebase that dereferences the ct extension without checking for NULL which could lead to crash.

Quoted source text, attributed separately from HOL analysis.