| Package | Affected versions | Patched versions |
|---|---|---|
| github.com/mattermost/mattermost-server | ≥ 11.4.0+incompatible, < 11.4.4+incompatible≥ 11.5.0+incompatible, < 11.5.2+incompatible< 5.3.2-0.20260327001745-7a339a6438f5 | 11.4.4+incompatible11.5.2+incompatible5.3.2-0.20260327001745-7a339a6438f5 |
| github.com/mattermost/mattermost-server/v5 | all versions | |
| github.com/mattermost/mattermost-server/v6 | all versions | |
| github.com/mattermost/mattermost/server/v8 | ≥ 11.4.0, < 11.4.4≥ 11.5.0, < 11.5.2< 8.0.0-20260327001745-7a339a6438f5 | 11.4.411.5.28.0.0-20260327001745-7a339a6438f5 |
| mattermost server | ≥ 11.4.0, < 11.4.4≥ 11.5.0, < 11.5.2 | 11.4.411.5.2 |
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
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