Vulnerability DatabaseCVE-2026-4635
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CVE-2026-4635
Published:May 22, 2026
Updated:June 11, 2026
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
Affected Packages
https://github.com/mattermost/mattermost.git (GITHUB):
Affected version(s) >=v11.4.0 <v11.4.5
Fix Suggestion:
Update to version v11.4.5
https://github.com/mattermost/mattermost.git (GITHUB):
Affected version(s) >=v11.5.0 <v11.5.4
Fix Suggestion:
Update to version v11.5.4
https://github.com/mattermost/mattermost.git (GITHUB):
Affected version(s) >=v10.11.0 <v10.11.15
Fix Suggestion:
Update to version v10.11.15
https://github.com/mattermost/mattermost.git (GITHUB):
Affected version(s) =v11.6.0 <v11.6.1
Fix Suggestion:
Update to version v11.6.1
github.com/mattermost/mattermost (GO):
Affected version(s) =v11.6.0 <v11.6.1
Fix Suggestion:
Update to version v11.6.1
github.com/mattermost/mattermost (GO):
Affected version(s) >=v11.5.0 <v11.5.4
Fix Suggestion:
Update to version v11.5.4
github.com/mattermost/mattermost (GO):
Affected version(s) >=v10.11.0 <v10.11.15
Fix Suggestion:
Update to version v10.11.15
github.com/mattermost/mattermost (GO):
Affected version(s) >=v11.4.0 <v11.4.5
Fix Suggestion:
Update to version v11.4.5
Related Resources (1)
https://mattermost.com/security-updates
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CVSS v4
Base Score:
7.1
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
LOW
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
6.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Weakness Type (CWE)
Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
CWE-362
EPSS
Base Score:
0.04