CVE-2026-3109
Missing timestamp validation in Zoom webhook handler
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
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- High
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
Missing timestamp validation in Zoom webhook handler
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
- Record
CVE-2026-3109- CVSS 3.1
- 2.2 Low
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-754
- Updated
- 2026-11-02
EUVDEUVD-2026-16236
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
- Record
EUVD-2026-16236- CVSS 3.1
- 2.2 Low
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-pv8w-wmj3-q39p
Mattermost Plugins versions <=11.4 10.11.11.0 fail to validate webhook request timestamps which...
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
- Record
GHSA-pv8w-wmj3-q39p- CVSS 3.1
- 2.2 Low
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-754
- Updated
- 2026-11-02
NVD
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
- Record
CVE-2026-3109- CVSS 3.1
- 2.2 Low
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-754
- Updated
- 2026-11-02
OSV
Missing timestamp validation in Zoom webhook handler
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
- Record
CVE-2026-3109- CVSS 3.1
- 2.2 Low
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-754
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-3109 is a low vulnerability (CVSS 2.2) in Mattermost, published March 26, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.30%, the 23rd percentile. No source names a fixed version.