MEDIUMCVSS v3.1 6.5Vulnerability
CVE-2026-18551
Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to validate the combination of guest and admin scheme roles which allows an authenticated attacker to escalate a guest account to team or channel admin via a crafted PUT request to the member roles API endpoint.. Mattermost Advisory ID: MMSA-2026-00752
Properties
- Severity
- MEDIUM
- Nvd fetched at
- 2026-10-20T21:14:08.448323+00:00
- Epss score
- 0.00222
- Cvss score
- 6.5
- Cvss severity
- MEDIUM
- Retrieved at
- 2026-10-21T01:24:49+00:00
- Last source
- FIRST EPSS
- Score
- 6.5
- Cvss version
- 3.1
- Cve id
- CVE-2026-18551
- Cvss vector
- CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
- First seen by Signal
- 2026-10-18T13:39:03+00:00
- Vector
- CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
- Published at
- 2026-10-16T07:17:12.260
- Last modified
- 2026-10-20T14:16:59.933
- Epss percentile
- 0.12016
Related Entities (1)
HAS_WEAKNESS (1)
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