CVE-2026-12882
Mattermost Markdown autolink parsing denial of service
CVSS Score
4.3
EPSS Score
0.0%
EPSS Percentile
0th
Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 fail to parse Markdown autolinks with unmatched trailing closing parentheses in linear time, which allows an authenticated user with permission to create posts to cause excessive server CPU consumption and degrade availability for other users via specially crafted post or message attachment content. Mattermost Advisory ID: MMSA-2026-00703
| CWE | CWE-407 |
| Vendor | mattermost |
| Product | mattermost |
| Published | Sep 14, 2026 |
| Last Updated | Sep 14, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low
Affected Versions
Mattermost / Mattermost
11.9.0 ≤ 11.9.0 11.8.0 ≤ 11.8.4 11.7.0 ≤ 11.7.7 10.11.0 ≤ 10.11.22
Credits
Adam Korczynski