Mattermost fails to preserve the redacted state of burn-on-read posts during deletion
Mattermost versions 11.3.x <= 11.3.0 fail to preserve the redacted state of burn-on-read posts during deletion which allows channel members to access unrevealed burn-on-read message contents via the WebSocket post deletion event. Mattermost Advisory ID: MMSA-2026-00579
02 / AFFECTED SOFTWARE
Affected packages
7 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
Mattermost versions 11.3.x <= 11.3.0 fail to preserve the redacted state of burn-on-read posts during deletion which allows channel members to access unrevealed burn-on-read message contents via the WebSocket post deletion event.. Mattermost Advisory ID: MMSA-2026-00579
Mattermost versions 11.3.x <= 11.3.0 fail to preserve the redacted state of burn-on-read posts during deletion which allows channel members to access unrevealed burn-on-read message contents via the WebSocket post deletion event. Mattermost Advisory ID: MMSA-2026-00579
Mattermost fails to preserve the redacted state of burn-on-read posts during deletion in github.com/mattermost/mattermost-server. NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions. (If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.) The additional affected modules and versions are: github.com/mattermost/mattermost-server/v5 before v5.3.2-0.20260127062706-c6b205f0d770.
05 / REFERENCES
Further evidence
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/2xxx/CVE-2026-2578.json
- https://mattermost.com/security-updates
- https://nvd.nist.gov/vuln/detail/CVE-2026-2578
- https://github.com/mattermost/mattermost
- https://github.com/mattermost/mattermost/commit/c6b205f0d77080ef805783de0628b9526af7faec
- https://github.com/advisories/GHSA-3rhr-jr63-hwq5