Plugin worker crash via unvalidated block properties
Published Sep 14, 2026 · Updated Sep 14, 2026
Denial of service in Mattermost Boards allows remote authenticated users with board editor access to crash the plugin worker. The block-creation path accepts a child block whose fields.properties value is not an object and passes it to code that assumes an object, terminating the worker. Exploitation requires editor access to a board; the resulting availability loss is confined to the Boards plugin worker rather than the entire server.
Summary
What happened
Denial of service in Mattermost Boards allows remote authenticated users with board editor access to crash the plugin worker. The block-creation path accepts a child block whose fields.properties value is not an object and passes it to code that assumes an object, terminating the worker. Exploitation requires editor access to a board; the resulting availability loss is confined to the Boards plugin worker rather than the entire server.
The record
- CVE
- CVE-2026-13417
- Published
- Sep 14, 2026
- Updated
- Sep 14, 2026
- Vendor
- Mattermost
- Product
- Mattermost
- Classifications
- T1499
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 14, 2026CVE publishedPublication date reported by the CVE source.
- Sep 14, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=10.11.0 <=10.11.22
- Affected versionversion=11.7.0 <=11.7.7
- Affected versionversion=11.8.0 <=11.8.4
- Affected versionversion=11.9.0 <=11.9.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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