CVE-2026-27454
Discourse has check revision visibility on posts endpoint
Description
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.
INFO
Published Date :
March 19, 2026, 9:17 p.m.
Last Modified :
March 25, 2026, 1:01 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update Discourse to version 2026.3.0-latest.1 or later.
- Update Discourse to version 2026.2.1 or later.
- Update Discourse to version 2026.1.2 or later.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-27454.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-27454 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-27454
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-27454 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-27454 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Mar. 25, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:* versions from (including) 2026.1.0 up to (excluding) 2026.1.2 *cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:* versions from (including) 2026.2.0 up to (excluding) 2026.2.1 *cpe:2.3:a:discourse:discourse:2026.3.0:*:*:*:latest:*:*:* Added Reference Type GitHub, Inc.: https://github.com/discourse/discourse/commit/8510fde30eb0d7f2dee822a95f6cf43b9ac943d0 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/discourse/discourse/commit/c0eeb5892f5d61ad62b057f4d468333a6e9f28c3 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/discourse/discourse/commit/c474fbd79d2bd231baafb4332970297d781f92ca Types: Patch Added Reference Type GitHub, Inc.: https://github.com/discourse/discourse/security/advisories/GHSA-fq69-f929-wp96 Types: Vendor Advisory -
New CVE Received by [email protected]
Mar. 19, 2026
Action Type Old Value New Value Added Description 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N Added CWE CWE-862 Added Reference https://github.com/discourse/discourse/commit/8510fde30eb0d7f2dee822a95f6cf43b9ac943d0 Added Reference https://github.com/discourse/discourse/commit/c0eeb5892f5d61ad62b057f4d468333a6e9f28c3 Added Reference https://github.com/discourse/discourse/commit/c474fbd79d2bd231baafb4332970297d781f92ca Added Reference https://github.com/discourse/discourse/security/advisories/GHSA-fq69-f929-wp96