CVE-2026-28736

** UNSUPPORTED WHEN ASSIGNED ** Focalboard version 8.0 fails to validate file ownership when serving uploaded files. This allows an authenticated attacker who knows a victim's fileID to read the content of the file. NOTE: Focalboard as a standalone product is not maintained and no fix will be issued.

Score

CVSS 3.1 4.3 Medium

Status

Analyzed - responsibledisclosure@mattermost.com

Published

2026-04-03

Last modified

2026-10-23

Weaknesses

CWE-639

Affected products

• Focalboard (Mattermost)

References

• https://github.com/mattermost-community/focalboard