Vulnerability in Mattermost

[ Description ]Official description

Mattermost versions <=11.9 11.1.9 11.5.8 11.10.7.0 fail to validate Zoom chat line length before slicing which allows an authenticated attacker to crash the Agents plugin via summarizing a Zoom chat transcription containing short continuation lines. Mattermost Advisory ID: MMSA-2026-00723

[ Fixes ]Fixes and patches

• Security bulletin: Mattermost MMSA-2026-00723Vendor patch or bulletin · CERT-FR · mattermost.com/security-updates, cited by CERT-FR CERTFR-2026-AVI-1388

[ Advisories ]Government CERT advisories

• CERT-FR27 Oct 2026CERTFR-2026-AVI-1388

  Vulnerability in Mattermost Server Translated from French

  A vulnerability has been discovered in Mattermost Server. It allows an attacker to cause remote denial of service.

  CVE-2026-116516
• BSI CERT-Bund26 Oct 2026WID-SEC-2026-4179

  Mattermost Server: Vulnerability allows denial of service Translated from German

  CVE-2026-116516

[ References ]References

• mattermost.com/security-updates