Mattermost Multiple Vulnerabilities Enable Remote Attack, CVSS 7.3
Summary
Germany's CERT-Bund issued security advisory WID-SEC-2026-1243 on 22 April 2026 advising of multiple vulnerabilities in Mattermost that enable an unspecified remote attack. The vulnerability has a CVSS Base Score of 7.3 (high) and a Temporal Score of 6.4 (medium), with remote attack confirmed as feasible. Mitigation measures are available. Affected versions include Mattermost below 11.7.0, 11.6.1, 11.5.4, 11.4.5, and 10.11.15, covering Linux, UNIX, Windows, and other operating systems.
“Ein Angreifer kann mehrere Schwachstellen in Mattermost ausnutzen, um einen nicht näher spezifizierten Angriff durchzuführen.”
IT administrators responsible for Mattermost deployments should inventory all installations across their environment and verify version numbers against the affected version list. Since the advisory confirms remote attack is possible and only states 'Mitigation available' without specifying patch contents, direct verification against Mattermost's official security release notes is necessary to confirm which update resolves each underlying vulnerability.
About this source
CERT-Bund is the German federal cybersecurity agency's incident response team, run by the BSI. Their advisory feed publishes vulnerability disclosures and active exploitation warnings for software in widespread enterprise use: VPN appliances, email servers, file transfer products, ERP systems, browsers, hypervisors. Around 280 advisories a month, each with a CVSS score, affected versions, and remediation guidance. The advisories are written in German but cover the same vulnerabilities that show up in CISA, NCSC-UK, and JPCERT bulletins, often hours earlier. Watch this if you patch enterprise software, run a SOC, or write detection rules. GovPing publishes each advisory with the affected vendor, CVSS score, and original CERT-Bund link.
What changed
CERT-Bund published security advisory WID-SEC-2026-1243 disclosing multiple vulnerabilities in Mattermost, a web-based instant-messaging service. The vulnerabilities carry a CVSS Base Score of 7.3 (high) with remote attack capability confirmed. Affected versions span multiple Mattermost releases across Linux, UNIX, Windows, and other platforms.
Organisations running Mattermost deployments should identify which versions are currently installed and update to a patched version as mitigation. The advisory does not specify which vulnerability was patched in which version — administrators should consult official Mattermost security advisories alongside this CERT-Bund alert to determine applicable patches.
Archived snapshot
Apr 23, 2026GovPing captured this document from the original source. If the source has since changed or been removed, this is the text as it existed at that time.
[WID-SEC-2026-1243] Mattermost: Mehrere Schwachstellen ermöglichen nicht spezifizierten Angriff CVSS Base Score 7.3 (hoch) CVSS Temporal Score 6.4 (mittel) Remoteangriff ja Datum 22.04.2026 Stand 23.04.2026 Mitigation ja
Betroffene Systeme
Betriebssystem
- Linux
- Sonstiges
- UNIX
- Windows
Produktbeschreibung
Mattermost ist ein webbasierter Instant-Messaging-Dienst.
Produkte
22.04.2026
- Mattermost Mattermost <11.7.0
Mattermost Mattermost <11.6.1
Mattermost Mattermost <11.5.4
Mattermost Mattermost <11.4.5
Mattermost Mattermost <10.11.15
Angriff
Angriff
Ein Angreifer kann mehrere Schwachstellen in Mattermost ausnutzen, um einen nicht näher spezifizierten Angriff durchzuführen. CVE Informationen Versionshistorie Feedback zum Advisory geben
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Source
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Source document text, dates, docket IDs, and authority are extracted directly from CERT-Bund.
The summary, classification, recommended actions, deadlines, and penalty information are AI-generated from the original text and may contain errors. Always verify against the source document.
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