GO-2026-4495
NoneCVSS
—
EPSS
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Published
Feb 23, 2026
CISA due date
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The record
Mattermost doesn't properly validate channel membership at the time of data retrieval in github.com/mattermost/mattermost-server
Affected packages
| Ecosystem | Package | Introduced | Fixed |
|---|---|---|---|
| Go | github.com/mattermost/mattermost-server | 10.11.0 | 10.11.10 |
| Go | github.com/mattermost/mattermost-server | 10.11.0+incompatible | 10.11.10+incompatible |
Related vulnerabilities
- CVE-2026-20796 Mattermost versions 10.11.x <= 10.11.9 fail to properly validate channel membership at… Same vulnerability
- GO-2026-4305 Mattermost Server vulnerable to CSRF if CORS is enabled in… Also affects github.com/mattermost/mattermost-server
- GO-2025-4259 Mattermost doesn't validate user channel membership when attaching Mattermost posts as… Also affects github.com/mattermost/mattermost-server
- GO-2026-4326 Mattermost is vulnerable to DoS due to infinite re-renders on API errors in… Also affects github.com/mattermost/mattermost-server
- GO-2025-4260 Mattermost doesn't verify that post actions invoking `/share-issue-publicly` were created… Also affects github.com/mattermost/mattermost-server
- GO-2026-4325 Mattermost is vulnerable to CPU exhaustion via crafted HTTP request in… Also affects github.com/mattermost/mattermost-server
- GO-2026-4282 Mattermost Server is vulnerable to channel invisibility DoS via misformatted post in… Also affects github.com/mattermost/mattermost-server
- GO-2026-4496 Mattermost doesn't validate user permissions when creating Jira issues from Mattermost… Also affects github.com/mattermost/mattermost-server