ZeroDay Findings
Sign inSign up

Findings

CVE-2026-27454

Discourse is an open-source discussion platform.

Published Mar 19, 2026 · updated Jun 17, 2026 · discourse discourse

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.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 19, 2026 · NIST NVD

    Detected

    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 conc

  2. Jun 17, 2026 · NIST NVD

    Updated

    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 conc

Affected

  • cpe discourse/discourseversion unspecified
  • cpe discourse/discourse2026.3.0

Sources

  • CVE.orgVulnerability recordCVE-2026-27454

    Official CVE identifier

    cve.org
  • NIST NVDVulnerability recordCVE-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

    nvd.nist.gov

References