CVE-2026-19600
Mattermost logs plaintext authentication tokens in debug-level server logs on failed auth attempts
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
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- High
- User interaction
- Required
What an attacker can affect
- Confidentiality
- High
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Mattermost logs plaintext authentication tokens in debug-level server logs on failed auth attempts
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
- Record
CVE-2026-19600- CVSS 3.1
- 4.5 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:N/A:N - Weakness
- CWE-532
- Updated
- 2026-11-02
EUVDEUVD-2026-102744
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
- Record
EUVD-2026-102744- CVSS 3.1
- 4.5 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:N/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-pqq2-2w3v-m8j5
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...
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
- Record
GHSA-pqq2-2w3v-m8j5- CVSS 3.1
- 4.5 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:N/A:N - Weakness
- CWE-532
- Updated
- 2026-11-02
NVD
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
- Record
CVE-2026-19600- CVSS 3.1
- 4.5 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:N/A:N - CVSS 3.1
- 4.9 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-532
- Updated
- 2026-11-02
OSV
Mattermost logs plaintext authentication tokens in debug-level server logs on failed auth attempts
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
- Record
CVE-2026-19600- CVSS 3.1
- 4.5 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:N/A:N - Weakness
- CWE-532
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-19600 is a medium vulnerability (CVSS 4.5) in Mattermost, published October 16, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.24%, the 14th percentile. No source names a fixed version.