Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to limit the length of the post ID array accepted by the bulk reactions endpoint which allows an authenticated user to cause excessive database load via a crafted request to {{POST /api/v4/posts/ids/reactions}}.. Mattermost Advisory ID: MMSA-2026-00771
Metrics
Affected Vendors & Products
References
| Link | Providers |
|---|---|
| https://mattermost.com/security-updates |
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History
Wed, 07 Oct 2026 17:00:00 +0000
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| First Time appeared |
Mattermost mattermost Server
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| CPEs | cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Mattermost mattermost Server
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Thu, 24 Sep 2026 04:30:00 +0000
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| Metrics |
ssvc
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Tue, 22 Sep 2026 16:30:00 +0000
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| First Time appeared |
Mattermost
Mattermost mattermost |
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| Vendors & Products |
Mattermost
Mattermost mattermost |
Tue, 22 Sep 2026 13:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to limit the length of the post ID array accepted by the bulk reactions endpoint which allows an authenticated user to cause excessive database load via a crafted request to {{POST /api/v4/posts/ids/reactions}}.. Mattermost Advisory ID: MMSA-2026-00771 | |
| Title | Unbounded post ID array in the bulk reactions endpoint allows denial of service | |
| Weaknesses | CWE-770 | |
| References |
| |
| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: Mattermost
Published: 2026-09-22T13:11:13.798Z
Updated: 2026-09-22T13:57:00.428Z
Reserved: 2026-09-22T13:09:02.237Z
Link: CVE-2026-95666
Updated: 2026-09-22T13:55:09.639Z
Status : Analyzed
Published: 2026-09-22T14:17:21.437
Modified: 2026-10-07T16:48:51.163
Link: CVE-2026-95666
No data.