CVE-2026-3472

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

State: Published
Severity: 3.5 Low
Published: Jun 26, 2026
Updated: Jun 26, 2026
Reserved: Mar 3, 2026

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

Scores

CVSS	Score	Vector	Source
3.1	3.5 Low	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N	Mattermost

Weaknesses

CWE-693 Protection Mechanism Failure

Affected Products

Product	Versions
MattermostMattermost	10.11.0 through 10.11.18Affected 11.6.0 through 11.6.3Affected 11.5.0 through 11.5.6Affected 11.7.0Not affected 10.11.19Not affected 11.6.4Not affected 11.5.7Not affected

References

MMSA-2026-00619vendor-advisory

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