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CVE-2026-19600
Mattermost logs plaintext authentication tokens in debug-level server logs on failed auth attempts
Medium4.5EPSS 0.24%
- Published
- Updated
- Reserved
- Assigned by
- Mattermost
Description
Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to sanitize authentication tokens before writing them to server log entries, which allows an attacker with access to server logs to obtain valid session tokens or OAuth access tokens and impersonate authenticated users via the debug-level Mattermost server log.. Mattermost Advisory ID: MMSA-2026-00763
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| MattermostCNA (assigner) | 3.1 | Medium4.5 | CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:N/A:N |
| NVDNVD · Analyzed | 3.1 | Medium4.9 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N |
- EPSS (exploitation in 30 days)
- 0.24% · top 85% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
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The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 4.5.
Weakness
Affected products
- affected 11.9.0 – ≤ 11.9.1
- affected 11.8.0 – ≤ 11.8.5
- affected 11.7.0 – ≤ 11.7.10
- affected 11.10.0 – ≤ 11.10.1
- unaffected 11.11.0
- unaffected 11.9.2
- unaffected 11.8.6
- unaffected 11.7.11
- unaffected 11.10.2
What to do
Solution: Update Mattermost to versions 11.11.0, 11.9.2, 11.8.6, 11.7.11, 11.10.2 or higher.
References (1)
- MMSA-2026-00763 (opens in a new tab)vendor-advisory
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-19600)Record last updated .