CVE-2026-6342 json
Group prefix matching bypass for subscriptions
published 2026-05-18 5 mo ago modified 2026-10-14 25 d ago also EUVD-2026-30745
- cvss
- 4.3
- 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 4%
- public exploits
- 0
- none known
Summary
Mattermost Plugins versions <=11.5 11.1.5 10.13.11 11.3.4.0 fail to appropriately check for valid namespaces which allows plugin users to create subscriptions to groups that were not whitelisted via creating groups that share the same prefix as a whitelisted group. Mattermost Advisory ID: MMSA-2026-00601
Patch / fix
- Mattermost Mattermost 10.11.14, 11.4.4, 11.5.2, 11.6.0
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 5 mo ago
Exploit prediction
0.15% chance of exploitation in the next 30 days, higher than 4% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 4.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N |
Affected products
- Mattermost Mattermost
Classification
- Weakness
-
- CWE-863 Incorrect Authorization
References
-
mattermost.com
/security-updates
vendor-advisory
Sources
- CVE List CVE-2026-6342
- NVD CVE-2026-6342
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.