ZDF
Sign inSign up

Vulnerabilities

Vulnerability · CVE-2026-27454

Discourse is an open-source discussion platform.

Published Mar 19, 2026 · catalog updated Jun 17, 2026 · Discourse is an open-source

Check if you run it

No confirmed exploitation is on record for CVE-2026-27454. EPSS is 0.99%. Act only if a listed version of Discourse is an open-source is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Discourse is an open-source).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium5.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.99%
Remediation
Advisory link
Affected products
cpe 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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe discourse/discourse2026.3.0

How to fix CVE-2026-27454

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-27454. EPSS is 0.99%. Act only if a listed version of Discourse is an open-source is installed.

Which versions are affected?

Compare what you have installed with 2026.3.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-862: Missing Authorization. EPSS 0.99%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

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

Sources

  • CVE.orgVulnerability recordCVE-2026-27454

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-27454

    30-day exploitation probability 1.0%

    first.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

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.