CVE-2026-25783
Denial of service via malformed User-Agent header in getBrowserVersion
CVSS Score
4.3
EPSS Score
0.0%
EPSS Percentile
0th
Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to properly validate User-Agent header tokens which allows an authenticated attacker to cause a request panic via a specially crafted User-Agent header. Mattermost Advisory ID: MMSA-2026-00586
| CWE | CWE-1287 |
| Vendor | mattermost |
| Product | mattermost |
| Published | Mar 16, 2026 |
| Last Updated | Mar 16, 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
11.3.0 ≤ 11.3.0 11.2.0 ≤ 11.2.2 10.11.0 ≤ 10.11.10
Credits
winfunc