Vulnerability in Mattermost Plugins (CVE-2026-3116)
Summary
Vulnerability in Mattermost Plugins (CVE-2026-3116). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
Mattermost Plugins versions <=11.4 11.0.4 11.1.3 11.3.2 10.11.11.0 fail to validate incoming request size which allows an authenticated attacker to cause service disruption via the webhook endpoint. Mattermost Advisory ID: MMSA-2026-00589
Source: NIST National Vulnerability Database NVD
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-3116 has been found in Mattermost Plugins.
Risk of unauthorized operations or information disclosure. CVSS score: 4.9/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Mattermost Plugins CVE-2026-3116" on the vendor's site.
CVE-2026-3116 (Mattermost Plugins) — CWE-400 / CVSS v3 4.9
Attack vector: remote (network-reachable) / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-400) exists in Mattermost Plugins.
Check the vendor advisory for the affected versions of Mattermost Plugins.
Severity: Medium (CVSS 4.9/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Mattermost Plugins を使っているサービスとバージョンを洗い出す。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- advisory mattermost.com
- advisory github.com
- advisory nvd.nist.gov