CVE-2026-3116
Analyzed Analyzed - Analysis Complete
Request Size Validation Flaw in Mattermost Plugins Causes DoS

Publication date: 2026-03-26

Last updated on: 2026-06-08

Assigner: Mattermost, Inc.

Description
Mattermost Plugins versions <=11.4 11.0.4 11.1.3 11.3.2 10.11.11.0 fail to validate incoming request size which allows an authenticated attacker to cause service disruption via the webhook endpoint. Mattermost Advisory ID: MMSA-2026-00589
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Meta Information
Published
2026-03-26
Last Modified
2026-06-08
Generated
2026-06-16
AI Q&A
2026-03-26
EPSS Evaluated
2026-06-15
NVD
CVE-2026-3116
EUVD
EUVD-2026-16246
Affected Vendors & Products
Showing 4 associated CPEs
Vendor Product Version / Range
mattermost mattermost_server From 10.11.0 (inc) to 10.11.12 (exc)
mattermost mattermost_server From 11.2.0 (inc) to 11.2.4 (exc)
mattermost mattermost_server From 11.3.0 (inc) to 11.3.2 (exc)
mattermost mattermost_server From 11.4.0 (inc) to 11.4.1 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-400 The product does not properly control the allocation and maintenance of a limited resource.
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Executive Summary

This vulnerability exists in Mattermost Plugins versions up to 11.4, 11.0.4, 11.1.3, 11.3.2, and 10.11.11.0. The issue is that these versions fail to validate the size of incoming requests properly. Because of this, an authenticated attacker can exploit the webhook endpoint by sending oversized requests, which can disrupt the service.

Impact Analysis

The impact of this vulnerability is a potential service disruption. An authenticated attacker can cause denial of service by exploiting the webhook endpoint with oversized requests, leading to unavailability or degraded performance of the affected Mattermost Plugins.

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