CVE-2026-27454 Details.
Discourse <=2026.2.0 - Hidden Post Revision Disclosure via revert_to Authorization Bypass
Atlas does not check this one. Needs a scripted sequence.
This check is a series of requests where each step depends on the last, often after logging in. Atlas runs single, read-only probes, so it does not run this one.
About CVE-2026-27454. What It Means.
Discourse versions before 2026.1.2, 2026.2.1, and 2026.3.0-latest.1 contain an authorization bypass in PostsController#display_post. The controller calls post.revert_to(params[:version]) directly whenever a version query parameter is present, without checking whether the corresponding PostRevision is hidden or whether the caller has permission to view edit history. By requesting a post at its publicly known version number via GET /posts/:id.json?version=<public_version>, the…
Affected Product. What Is Hit.
- Vendor
- discourse
- Product
- Discourse
FAQ
Common Questions.
Discourse <=2026.2.0 - Hidden Post Revision Disclosure via revert_to Authorization Bypass. Discourse versions before 2026.1.2, 2026.2.1, and 2026.3.0-latest.1 contain an authorization bypass in PostsController#display_post. The controller calls post.revert_to(params[:version]) directly whenever a version query parameter is present, without checking whether the corresponding PostRevision is hidden or whether the caller has permission to view edit history. By requesting a post at its publicly known version number via GET /posts/:id.json?version=<public_version>, the…
No. This check is a series of requests where each step depends on the last, often after logging in. Atlas runs single, read-only probes, so it does not run this one. The facts about CVE-2026-27454 are on this page, and you can request a demo to see how Brandefense watches your whole external attack surface.
CVE-2026-27454 is not on the CISA Known Exploited Vulnerabilities list at the time of writing, but it is still worth fixing.
Update Discourse to the latest version from the vendor, or follow the vendor's advice to switch off the affected feature. Vendor links are listed on this page when they are known.
This page lists the public facts about CVE-2026-27454. Atlas does not run a check for it, so nothing here says whether a particular site is affected.