CVE-2026-3472

Name of the Vulnerable Software and Affected Versions Mattermost versions 10.11.0 through 10.11.18 Mattermost versions 11.5.0 through 11.5.6 Mattermost versions 11.6.0 through 11.6.3

Description An issue exists where markdown image rendering restrictions are not properly applied to AI bot tool result posts. This allows an authenticated attacker to exfiltrate data to an external server by injecting markdown image syntax into the tool result content that is subsequently rendered by a victim's client.

Recommendations Update Mattermost versions 10.11.0 through 10.11.18 to a version newer than 10.11.18. Update Mattermost versions 11.5.0 through 11.5.6 to a version newer than 11.5.6. Update Mattermost versions 11.6.0 through 11.6.3 to a version newer than 11.6.3.