CVE-2026-0998 Mattermost Zoom Plugin allows unauthorized meeting creation and post modification via insufficient API access controls
Attackers can create unauthorized Zoom meetings and modify arbitrary posts by bypassing user identity and ownership checks in the API.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-0998?
CVE-2026-0998 is a medium-severity missing authorization vulnerability in Mattermost Mattermost Server, published on 16 Feb 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
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
Weakness: CWE-862
Which versions are affected by CVE-2026-0998?
3 open source packages ship an affected version, including github.com/mattermost/mattermost-plugin-zoom. It affects 2 products.
| Package | Affected | Fixed in |
|---|---|---|
github.com/mattermost/mattermost-plugin-zoom Go | All versions | 1.12.0 |
github.com/mattermost/mattermost-plugin-zoom Go | All versions | 1.12.0 |
github.com/mattermost/mattermost-plugin-zoom Go | All versions | 1.12.0 |
Products include Mattermost Mattermost Server, Mattermost Zoom.
How do I fix CVE-2026-0998?
Upgrade github.com/mattermost/mattermost-plugin-zoom to 1.12.0 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-0998 being exploited?
There is no known exploitation of CVE-2026-0998 in the wild and no public exploit code.
Other vulnerabilities in Mattermost Mattermost Server
- CVE-2025-12419 Account takeover on OAuth/OpenID-enabled servers
- CVE-2025-12421 Account Takeover via Code Exchange Endpoint
- CVE-2025-4981 Path Traversal Leading to RCE by Any Authenticated Mattermost User
- CVE-2025-20051 Arbitrary file read via block duplication in Mattermost Boards
- CVE-2025-25279 Arbitrary file read in Mattermost Boards via import & export board archive
Sources
Also known as GHSA-w65c-fvp5-fvc5, GO-2026-4525.