CVE-2026-3472

LOW

Markdown image rendering bypass in AI bot tool result posts in Mattermost

Title source: cna
STIX 2.1

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

References (1)

Core 1
Core References
Vendor Advisory vendor-advisory
MMSA-2026-00619
https://mattermost.com/security-updates

Scores

CVSS v3 3.5
EPSS 0.0019
EPSS Percentile 9.3%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-693
Status published
Products (8)
Mattermost/Mattermost 10.11.0 - 10.11.18
Mattermost/Mattermost 10.11.19
Mattermost/Mattermost 11.5.0 - 11.5.6
Mattermost/Mattermost 11.5.7
Mattermost/Mattermost 11.6.0 - 11.6.3
Mattermost/Mattermost 11.6.4
Mattermost/Mattermost 11.7.0
mattermost/mattermost_server 10.11.0 - 10.11.19
Published Jun 26, 2026
Tracked Since Jun 26, 2026