CVE-2026-3472
Markdown image rendering bypass in AI bot tool result posts in Mattermost
Description
Mattermost versions 10.11.x <= 10.11.18, 11.6.x <= 11.6.3, 11.5.x <= 11.5.6 fail to properly apply markdown image rendering restrictions to AI bot tool result posts, which allows an authenticated attacker to exfiltrate data to an attacker-controlled server via injecting markdown image syntax into tool result content rendered by a victim's client.. Mattermost Advisory ID: MMSA-2026-00619
INFO
Published Date :
June 26, 2026, 3:16 p.m.
Last Modified :
June 29, 2026, 7:27 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-3472
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.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | LOW | 9302f53e-dde5-4bf3-b2f2-a83f91ac0eee | ||||
| CVSS 3.1 | LOW | [email protected] |
Solution
- Update Mattermost to version 10.11.19 or later.
- Update Mattermost to version 11.6.4 or later.
- Update Mattermost to version 11.5.7 or later.
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-2026-3472.
| URL | Resource |
|---|---|
| https://mattermost.com/security-updates | Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-3472 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-2026-3472
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-2026-3472 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-3472 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.
-
Initial Analysis by [email protected]
Jun. 29, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* versions from (including) 10.11.0 up to (excluding) 10.11.19 *cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* versions from (including) 11.5.0 up to (excluding) 11.5.7 *cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* versions from (including) 11.6.0 up to (excluding) 11.6.4 Added Reference Type Mattermost, Inc.: https://mattermost.com/security-updates Types: Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 26, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-3472', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-26T15:41:02.864491Z'} -
New CVE Received by [email protected]
Jun. 26, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'Mattermost', 'product': 'Mattermost', 'versions': [{'status': 'affected', 'version': '10.11.0', 'versionType': 'semver', 'lessThanOrEqual': '10.11.18'}, {'status': 'affected', 'version': '11.6.0', 'versionType': 'semver', 'lessThanOrEqual': '11.6.3'}, {'status': 'affected', 'version': '11.5.0', 'versionType': 'semver', 'lessThanOrEqual': '11.5.6'}, {'status': 'unaffected', 'version': '11.7.0'}, {'status': 'unaffected', 'version': '10.11.19'}, {'status': 'unaffected', 'version': '11.6.4'}, {'status': 'unaffected', 'version': '11.5.7'}], 'defaultStatus': 'unaffected'}] Added Description Mattermost versions 10.11.x <= 10.11.18, 11.6.x <= 11.6.3, 11.5.x <= 11.5.6 fail to properly apply markdown image rendering restrictions to AI bot tool result posts, which allows an authenticated attacker to exfiltrate data to an attacker-controlled server via injecting markdown image syntax into tool result content rendered by a victim's client.. Mattermost Advisory ID: MMSA-2026-00619 Added CVSS V3.1 AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N Added CWE CWE-693 Added Reference https://mattermost.com/security-updates