CVE-2026-27454

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, requesting /posts/:id.json?version=X bypassed authorization checks on post revisions. The display_post method called post.revert_to directly without verifying whether the revision was hidden or if the user had permission to view edit history. This meant hidden revisions (intentionally concealed by staff) could be read by any user by simply enumerating version numbers. Starting in versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, Discourse looks up the PostRevision and call guardian.ensure_can_see! before reverting, consistent with how the /posts/:id/revisions/:revision endpoint already authorizes access. No known workarounds are available.

Affected products

Discourse

Discourse

< 2026.1.2, 2026.2.1, 2026.3.0

Fix

Available

CVSS 3.1

5.3 MEDIUM

EPSS

0.5% (38th percentile)

Weakness

CWE-862

NVD status

Analyzed

Published

2026-03-19

No exploit for CVE-2026-27454 has been indexed yet. Our index is built from live traffic and upstream syncs, so this page can only say what it knows — not that no exploit exists.