CVE-2026-274545.3MediumCWE-862

CVE-2026-27454: Discourse has check revision visibility on posts endpoint

discourse

Affected: discourse · Exploitation: check available, not yet exploited

Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.

1.0%probability of exploitation in the next 30 days

62nd percentile

050100

Higher than 62% of scored CVEs

5.3MediumCVSS 3.1

LowMediumHighCrit.

DescriptionCVE.org

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 products1

From the CVE record. A product or version that is not listed is unknown, not unaffected.

discourse · discourse>= 2026.1.0-latest, < 2026.1.2; >= 2026.2.0-latest, < 2026.2.1; = 2026.3.0-latest

On the Atlas

Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.

Open the Atlas

Exploitation: Check available, not yet exploited. A public nuclei template can confirm it on a system you are authorised to test.
CISA KEV: Not listed
Public check: Discourse <=2026.2.0 - Hidden Post Revision Disclosure via revert_to Authorization Bypass · nuclei template in projectdiscovery/nuclei-templates
Weakness: Missing Authorization · Access Control
Vendor: discourse
Published: March 2026
Band: Check available, not yet exploited, March 2026

CoverageNo articles yet

No CyberSIXT article names CVE-2026-27454 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.