CVE-2026-19621
Mattermost leaks interactive-message integration secrets to non-admin users via post-deletion events and thread reads
CVSS Score
6.5
EPSS Score
0.0%
EPSS Percentile
0th
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 strip action integration secrets from post payloads before broadcasting post-deletion web socket events and returning thread API responses, which allows an authenticated channel member to obtain server-side webhook URLs and authentication context from interactive-message posts via the post_deleted websocket event or the threads REST API.. Mattermost Advisory ID: MMSA-2026-00766
| CWE | CWE-200 |
| Vendor | mattermost |
| Product | mattermost |
| Published | Oct 16, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None
Affected Versions
Mattermost / Mattermost
11.10.0 ≤ 11.10.0 11.7.0 ≤ 11.7.9 11.9.0 ≤ 11.9.1 11.8.0 ≤ 11.8.5
Credits
Edgar Bellot Micó