CVE-2026-3109
Missing timestamp validation in Zoom webhook handler
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
INFO
Published Date :
March 26, 2026, 5:16 p.m.
Last Modified :
March 26, 2026, 5:16 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-3109
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | LOW | 9302f53e-dde5-4bf3-b2f2-a83f91ac0eee | ||||
| CVSS 3.1 | LOW | [email protected] |
Solution
- Update Mattermost plugins to version 11.4 or later.
- Verify timestamp validation for all webhooks.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-3109.
| URL | Resource |
|---|---|
| https://mattermost.com/security-updates |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-3109 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-3109
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-3109 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-3109 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Mar. 26, 2026
Action Type Old Value New Value Added 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 Added CVSS V3.1 AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L Added CWE CWE-754 Added Reference https://mattermost.com/security-updates