Medium severity · published Mar 26, 2026
CVE-2026-3116
Improper Input Validation in Zoom Plugin Webhook Handler
4.9
CVSS
0.4%
EPSS
No
On KEV
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
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
High
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 29% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MA
Mattermost · Mattermost
through 11.0.4; through 11.1.3; through 11.3.2; through 10.11.11 · source: vendor
MS
Mattermost Server · Mattermost
10.11.0 before 10.11.12; 11.2.0 before 11.2.4; 11.3.0 before 11.3.2; 11.4.0 before 11.4.1 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-3116
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-3116
Vendor Advisory
https://mattermost.com/security-updates
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