CVE-2026-4635
Persistent notification timing attack causing server denial of service
CVSS Score
6.5
EPSS Score
0.0%
EPSS Percentile
0th
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to archive the channel before removing persistent notifications which allows authenticated user to crash the server via timing the creation of persistent notification message between the server deleting existing persistent notifications and archiving the channel.. Mattermost Advisory ID: MMSA-2026-00637
| CWE | CWE-362 |
| Vendor | mattermost |
| Product | mattermost |
| Published | May 22, 2026 |
| Last Updated | May 22, 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:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
Mattermost / Mattermost
11.6.0 ≤ 11.6.0 11.5.0 ≤ 11.5.3 11.4.0 ≤ 11.4.4 10.11.0 ≤ 10.11.14
Credits
daw10