CVE-2026-15754Missing per-channel team-scope check in ABAC access control policy unassign allows cross-team policy removal
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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Mattermost versions 11.7.x <= 11.7.6, 11.8.x <= 11.8.3 The access control policy unassign endpoint fails to re-validate that each target channel still belongs to the requesting admin's team, which allows an authenticated team administrator to remove ABAC (attribute-based access control) policy assignments from channels outside their team via the policy unassign API after a channel has been moved to another team.. Mattermost Advisory ID: MMSA-2026-00718
- CVSS
- 4.2 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:H/A:N
- Weakness (CWE)
- CWE-863
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Mattermost
- NVD analysis
- Analyzed
- Record last updated
- Aug 17, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Mattermost Mattermost mattermost:mattermost (from the name) | from 11.7.0 through 11.7.6; from 11.8.0 through 11.8.3; 11.9.0 not affected; 11.7.7 not affected; 11.8.4 not affected | CNA record |
mattermost mattermost_server mattermost:mattermost_server | from 11.7.0 before 11.7.7; from 11.8.0 before 11.8.4 | NVD |
References
- https://mattermost.com/security-updatesvendor-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.