netfilter: synproxy: fix unaligned memory access in timestamp adjustment (CVE-2026-80637) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-80637

netfilter: synproxy: fix unaligned memory access in timestamp adjustment

Answer in brief

CVE-2026-80637 records a Unknown severity vulnerability in netfilter: synproxy: fix unaligned memory access in timestamp adjustment. 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	>=48b1de4c110a7afa4b85862f6c75af817db26fad <2b8e7aaa38002d8ee2f48d87b1f392eadd8e98c4 \|\| >=48b1de4c110a7afa4b85862f6c75af817db26fad <5c9c67cf7a3d16051dfb90e98836f530964dfb8e \|\| >=48b1de4c110a7afa4b85862f6c75af817db26fad <ea3d2caa5bfacf5db5c1cad521ca5d9144edd9a7 \|\| >=48b1de4c110a7afa4b85862f6c75af817db26fad <992c20bc8a4aba220c8b95b467d049289778dad6	2b8e7aaa38002d8ee2f48d87b1f392eadd8e98c4, 5c9c67cf7a3d16051dfb90e98836f530964dfb8e, ea3d2caa5bfacf5db5c1cad521ca5d9144edd9a7, 992c20bc8a4aba220c8b95b467d049289778dad6
Linux/Linuxgeneric	3.12	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 2b8e7aaa38002d8ee2f48d87b1f392eadd8e98c4 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: synproxy: fix unaligned memory access in timestamp adjustment Use get_unaligned_be32() and put_unaligned_be32() to safely read and write the timestamp fields. This prevents performance degradation due to unaligned memory access or even a crash on strict alignment architectures. This follows the implementation of timestamp parsing in the networking stack at tcp_parse_options() and synproxy_parse_options().

Quoted source text, attributed separately from HOL analysis.