net: l2tp: do not propagate multicast notification errors (CVE-2026-80996) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-80996

net: l2tp: do not propagate multicast notification errors

Answer in brief

CVE-2026-80996 records a Unknown severity vulnerability in net: l2tp: do not propagate multicast notification errors. 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 Sep 11, 2026Updated Sep 11, 2026Source checked Sep 11, 2026First seen by HOL Sep 11, 2026Material review Sep 11, 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	>=33f72e6f0c67f673fd0c63a8182dbd9ffb8cf50b <0fe037d5eaad938aa3e9143ee071aa237750b42b \|\| >=33f72e6f0c67f673fd0c63a8182dbd9ffb8cf50b <9c340473f4822bb31b151c19afd17448eda5acd1 \|\| >=33f72e6f0c67f673fd0c63a8182dbd9ffb8cf50b <50c4038f1670bf9a80c6a58ae83d1602decd8481 \|\| >=33f72e6f0c67f673fd0c63a8182dbd9ffb8cf50b <af20e269f7459d2ce69887fdf2fad7caf986c865	0fe037d5eaad938aa3e9143ee071aa237750b42b, 9c340473f4822bb31b151c19afd17448eda5acd1, 50c4038f1670bf9a80c6a58ae83d1602decd8481, af20e269f7459d2ce69887fdf2fad7caf986c865
Linux/Linuxgeneric	4.0	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 0fe037d5eaad938aa3e9143ee071aa237750b42b if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 11, 2026

Sources and claim methodology

Upstream source description

In the Linux kernel, the following vulnerability has been resolved: net: l2tp: do not propagate multicast notification errors The tunnel create, tunnel modify, session create, and session modify netlink handlers send multicast notifications through helpers that can fail while allocating or encoding a message, or while multicasting it. For tunnel and session create/modify, a notification is sent after the live operation has completed. Returning a best-effort notification error as the command result can therefore report failure for an operation that already committed and can cause callers to retry and accumulate live objects. Keep sending notifications for listener visibility, but do not propagate their best-effort status as the command result. This also keeps the tunnel modify command consistent with the other notification-only paths.

Quoted source text, attributed separately from HOL analysis.