Mattermost Plugins <=11.4 Request Size Validation Bypass in Webhook Endpoint
CVE-2026-3116 Published on March 26, 2026
Improper Input Validation in Zoom Plugin Webhook Handler
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
Vulnerability Analysis
CVE-2026-3116 is exploitable with network access, and requires user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Type
What is a Resource Exhaustion Vulnerability?
The software does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources.
CVE-2026-3116 has been classified to as a Resource Exhaustion vulnerability or weakness.
Products Associated with CVE-2026-3116
Want to know whenever a new CVE is published for MatterMost? stack.watch will email you.
Affected Versions
Mattermost:- Before and including 11.0.4 is affected.
- Before and including 11.1.3 is affected.
- Before and including 11.3.2 is affected.
- Before and including 10.11.11 is affected.
- Version 11.5.0 is unaffected.
- Version 11.4.1 is unaffected.
- Version 11.3.2 is unaffected.
- Version 11.2.4 is unaffected.
- Version 10.11.12 is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.