CVE-2026-9820
Multiple vulnerabilities have been discovered in Mattermost products. They allow an attacker to cause an unspecified security issue by the editor.
CSIRTS triage
- What
- Multiple unspecified vulnerabilities in Mattermost products allow attackers to cause unspecified security issues through the editor.
- Who is affected
- All Mattermost product deployments are affected; specific versions are not stated.
- Urgency
- Moderate urgency; no active exploitation reported but multiple CVEs indicate broad exposure.
- Action
- Check Mattermost security advisory page for affected versions and apply available patches or updates.
AI-assisted analysis generated from the source advisory — verify against the original.
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Exploitation outlook
- Low exploitation risk0.15% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 5% of all EPSS-scored CVEs.
Advisory coverage (2)
- lowCVE-2026-9820: Mattermost versions 11.7.x <= 11.7.2, 10.11.x <= 10.11.19 fail to sanitize team objects returne…nvd · 2026-07-13
- unknownMultiple vulnerabilities in Mattermost products (June 15, 2026)cert-fr-avis · 2026-06-15
External references
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[](https://www.csirts.com/cve/CVE-2026-9820)