CVE-2026-5139VulnerabilityPublished 21 May 2026Updated 22 Jun 2026

Mattermost (Desktop, Server und Mobile): Mehrere Schwachstellen

Affects Bundesamt für Sicherheit in der Informationstechnik MattermostSource GCVE Database

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Mentioned vulnerabilities

Not known to be exploited : upgrade to 11.8.0 when convenient.

Data as of 9 Nov 2026, 23:24 UTC

Severity

Medium

Rated by Threat Radar · No CVSS score from NVD or the CNA

EPSS: 0.2% chance of exploitation in 30 days – higher than 21% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 11.8.0

Exploitation evidence

Disclosed: evidence found.
CVE published 21 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 9 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

bundesamt-f-r-sicherheit-in-de

What to do

Upgrade Bundesamt für Sicherheit in der Informationstechnik Mattermost to 11.8.0.

Affected software

Product	Affected	Fixed in
Bundesamt für Sicherheit in der Informationstechnik Mattermost	Affected <11.8.0	Fixed in 11.8.0

Description

Multiple vulnerabilities have been identified in Mattermost, a web-based instant messaging service, affecting its Desktop, Server, and Mobile versions. The advisory from the Bundesamt für Sicherheit in der Informationstechnik references six CVEs but does not provide detailed technical descriptions or CVSS scores. There are no known exploits in the wild at this time.

Impact

The impact of these vulnerabilities cannot be precisely determined from the available information as no specific descriptions or CVSS scores are provided. Without further data, the potential impact remains unclear.

Summary

This advisory reports multiple security vulnerabilities in Mattermost across its Desktop, Server, and Mobile platforms. Six CVEs are associated with this report (CVE-2026-5139, CVE-2026-6062, CVE-2026-6673, CVE-2026-8074, CVE-2026-9162, CVE-2026-22880). However, no technical details beyond their existence are provided, and no CVSS scores or exploitation details are available. The vendor advisory (WID-SEC-W-2026-1650) does not include patch or remediation information. The vulnerabilities are catalogued by the German Federal Office for Information Security (BSI), but the lack of further data limits detailed analysis.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 23 Jun 2026, 15:55 UTC

Technical details

References

Community reviews

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