Vulnerability · CVE-2026-0998
Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 and Mattermost Plugin Zoom versions <=1.11.0 fail to validate user identity and post ownership in the {{/
Published Feb 16, 2026 · catalog updated Feb 17, 2026 · Mattermost Mattermost
Last checked Nov 12, 2026. A connected source was read within the last 7 days.
Check if you run it
No confirmed exploitation is on record for CVE-2026-0998. EPSS is 0.18%. Act only if a listed version of Mattermost Mattermost is installed.
Gaps on this record
- No vendor fix or required action is stored. Compare the linked advisory before you change production.
Same product and reporting
- CVE-2026-13411 · Medium
- CVE-2026-24661 · Medium
- CVE-2026-21388 · Medium
- CVE-2026-3524 · High
- CVE-2026-1628 · Medium
- Severity
- Medium4.3
- Known exploitation
- Not in CISA/VulnCheck KEV
- EPSS
- 0.18%
- Remediation
- Advisory link
- Affected products
- vendor Mattermost Mattermost 11.2.0 ≤11.2.1
Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 and Mattermost Plugin Zoom versions <=1.11.0 fail to validate user identity and post ownership in the {{/api/v1/askPMI}} endpoint which allows unauthorized users to start Zoom meetings as any user and overwrite arbitrary posts via direct API calls with manipulated user IDs and post data.. Mattermost Advisory ID: MMSA-2025-00534
Are you affected?
Enter the version you run. The result uses only the ranges stored on this record.
The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.
- vendor Mattermost Mattermost 11.2.0 ≤11.2.111.2.0 ≤11.2.1
How to fix CVE-2026-0998
No stored fix
No vendor fix text is stored. Use the linked advisory before you change production.
Version check
Seen in 11.2.0 ≤11.2.1
Advisory
Open the cve_org record and follow its fix.
Official advisories
What to do
Three questions, each answered from this record only. Confirm the vendor advisory before you patch.
Should you patch?
No confirmed exploitation is on record for CVE-2026-0998. EPSS is 0.18%. Act only if a listed version of Mattermost Mattermost is installed.
Which versions are affected?
Compare what you have installed with Mattermost Mattermost 11.2.0 ≤11.2.1 11.2.0 ≤11.2.1. Compare the installed version with the linked vendor advisory before you change production.
What should an analyst verify?
No weakness class is stored. EPSS 0.18%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.
Code
The project this record applies to. Exploit listings stay in References.
No public source repository is identified for this product.
Timeline
Detection, updates, and resolution for this record.
Feb 16, 2026 · EUVD
Detected
Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 and Mattermost Plugin Zoom versions <=1.11.0 fail to validate user identity and post ownership in the {{/api/v1/askPMI}} endpoint which allows unauthorized users to start Zoom meetings as any user and overwrite arbitrary posts via direct API calls with manipulated user IDs and post data.. Mattermost Advisory ID: MMSA-2025-0
Feb 17, 2026 · EUVD
Updated
Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 and Mattermost Plugin Zoom versions <=1.11.0 fail to validate user identity and post ownership in the {{/api/v1/askPMI}} endpoint which allows unauthorized users to start Zoom meetings as any user and overwrite arbitrary posts via direct API calls with manipulated user IDs and post data.. Mattermost Advisory ID: MMSA-2025-0
Sources
- CVE.orgVulnerability recordCVE-2026-0998
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2026-0998
30-day exploitation probability 0.18%
first.org - EUVDVulnerability recordEUVD-2026-6100
Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 and Mattermost Plugin Zoom versions <=1.11.0 fail to validate user identity and post ownership in the {{/api/v1/askPMI}} endpoint which allows unauthorized users to start Zoom meetings as any user and over
euvd.enisa.europa.eu
References
Freshness
Last verified in this catalog Nov 12, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.
- FIRST EPSSNov 12, 2026
- CVE.orgNov 10, 2026
- EUVDNov 9, 2026