Multiple vulnerabilities in Mattermost Desktop App (June 18, 2026)

unknownCVE-2026-9602 CVE-2026-8075

Multiple vulnerabilities were discovered in Mattermost Desktop App. They allow an attacker to cause remote denial of service and an unspecified security issue by the vendor.

CSIRTS triage

vendor: Mattermost product: Desktop App Denial of serviceOther

What: Remote denial of service and an unspecified security issue were discovered in Mattermost Desktop App.
Who is affected: Users of Mattermost Desktop App are affected, though specific versions are not stated.
Urgency: Moderate urgency due to denial of service capability, though severity is unknown and no active exploitation has been reported.
Action: Update Mattermost Desktop App to the patched version when available; check vendor advisories for specific version numbers and remediation steps.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: CERT-FR Avis de sécurité (FR · national-cert · site)
Severity: unknown
Published: 2026-06-18
Exploitation: Not in CISA KEV at last sync
Language: Machine-translated to English — verify against the original

Original advisory: https://www.cert.ssi.gouv.fr/avis/CERTFR-2026-AVI-0777/

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-96020.24% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 15% of all EPSS-scored CVEs.
Low exploitation riskCVE-2026-80750.24% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 15% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-9602	coverage & exploitation status	NVD · CVE.org
CVE-2026-8075	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

Recent advisories for Mattermost Desktop App

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

unknownMultiple vulnerabilities in Mattermost Desktop App (August 18, 2026)cert-fr-avis · 2026-08-18
lowCVE-2026-75587: Mattermost Desktop App versions <=6.2 6.2.2.0 fail to redact the pre-auth secret when generati…nvd · 2026-08-17
mediumCVE-2026-9602: Mattermost Desktop App versions <=6.2 6.0.2 5.6.13.0 fail to validate payloads sent from the Ma…nvd · 2026-07-17
mediumCVE-2026-8075: Mattermost Desktop App versions <=6.2 5.5.13 6.0.2.0 fail to properly null check when checking …nvd · 2026-07-17