Low severity · published Mar 26, 2026
CVE-2026-3109
Missing timestamp validation in Zoom webhook handler
2.2
CVSS
0.3%
EPSS
No
On KEV
Description
Mattermost Plugins versions <=11.4 10.11.11.0 fail to validate webhook request timestamps which allows an attacker to corrupt Zoom meeting state in Mattermost via replayed webhook requests. Mattermost Advisory ID: MMSA-2026-00584
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L
Attack vector
Network
Complexity
High
Privileges
High
User interaction
None
Confidentiality
None
Integrity
None
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 23% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MA
Mattermost · Mattermost
through 10.11.11 · source: vendor
MS
Mattermost Server · Mattermost
10.11.0 before 10.11.12 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-3109
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-3109
Vendor Advisory
https://mattermost.com/security-updates
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