CVE-2026-19541 json
Outgoing OAuth connection client secret exposure during connection validation
published 24d ago modified 11d ago also EUVD-2026-102805
- cvss
- 6.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 13%
- public exploits
- 0
- none known
Summary
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 require re-entry of the stored client secret when validating an outgoing OAuth connection, which allows an authenticated user with permission to manage outgoing OAuth connections to obtain the secret via pointing the token URL at an attacker-controlled endpoint and triggering validation.. Mattermost Advisory ID: MMSA-2026-00761
Patch / fix
- Mattermost Mattermost 11.7.11, 11.8.6, 11.9.2, 11.10.2, 11.11.0
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Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 24d ago
Exploit prediction
0.22% chance of exploitation in the next 30 days, higher than 13% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N |
Affected products
- Mattermost Mattermost
Classification
- Weakness
-
- CWE-201 Insertion of Sensitive Information Into Sent Data
References
-
mattermost.com
/security-updates
vendor-advisory
Sources
- CVE List CVE-2026-19541
- NVD CVE-2026-19541
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