sctp: fix stream->outcnt underflow on duplicate RECONF responses (CVE-2026-89476) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-89476

sctp: fix stream->outcnt underflow on duplicate RECONF responses

Answer in brief

CVE-2026-89476 records a Unknown severity vulnerability in sctp: fix stream->outcnt underflow on duplicate RECONF responses. 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	>=11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 <2d867663c563e8009257b9edf9c8ec75d9bbf19a \|\| >=11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 <d02a5794c3deedcb8476d017fcee2b7aaedab2e1 \|\| >=11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 <8320cbd81bc21a1ca6ebdf70ad610ebc5ef1bd68 \|\| >=11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 <3faf13aff243ca9f78d08b1a2956ef5a6fc77b6e	2d867663c563e8009257b9edf9c8ec75d9bbf19a, d02a5794c3deedcb8476d017fcee2b7aaedab2e1, 8320cbd81bc21a1ca6ebdf70ad610ebc5ef1bd68, 3faf13aff243ca9f78d08b1a2956ef5a6fc77b6e
Linux/Linuxgeneric	4.12	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 2d867663c563e8009257b9edf9c8ec75d9bbf19a 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: sctp: fix stream->outcnt underflow on duplicate RECONF responses A cached RECONF chunk may contain more than one request parameter. A duplicate response can therefore find and process the same ADD_OUT request again while another parameter is still outstanding, rolling back outcnt twice and possibly underflowing it. Track outstanding request types as bits and clear each bit after its first response. Later responses for the same request are then ignored.

Quoted source text, attributed separately from HOL analysis.