GHSA-xvcx-mgpc-5xh3
Mattermost doesn't validate the X-Requested-With header on the burn-on-read reveal endpoint
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| Go | github.com/mattermost/mattermost/server/v8 | >= 11.5.0, < 11.5.2 | 11.5.2 |
| Go | github.com/mattermost/mattermost/server/v8 | >= 11.4.0, < 11.4.4 | 11.4.4 |
| Go | github.com/mattermost/mattermost/server/v8 | < 8.0.0-20260327001745-7a339a6438f5 | 8.0.0-20260327001745-7a339a6438f5 |
| Go | github.com/mattermost/mattermost-server | < 5.3.2-0.20260327001745-7a339a6438f5 | 5.3.2-0.20260327001745-7a339a6438f5 |
Details
As written in the advisory (Markdown source, shown as plain text).
Mattermost versions 11.5.x <= 11.5.1, 11.4.x <= 11.4.3 fail to validate the X-Requested-With header on the burn-on-read reveal endpoint which allows an authenticated channel member to force the reveal of a burn-on-read message without recipient consent via a crafted Markdown image tag.. Mattermost Advisory ID: MMSA-2026-00636
References
External links from the advisory. They lead to third-party sites.