Discourse up to 2026.1.1/2026.2.0/2026.3.0-latest /posts/ display_post authorization

CVSS Meta Temp Score
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CTI Interest Score
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5.2$0-$5k0.00

Summaryinfo

A vulnerability classified as problematic was found in Discourse up to 2026.1.1/2026.2.0/2026.3.0-latest. This impacts the function display_post of the file /posts/. Such manipulation leads to authorization. This vulnerability is uniquely identified as CVE-2026-27454. The attack can be launched remotely. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Discourse up to 2026.1.1/2026.2.0/2026.3.0-latest and classified as problematic. Affected by this issue is the function display_post of the file /posts/. The manipulation with an unknown input leads to a authorization vulnerability. Using CWE to declare the problem leads to CWE-862. The product does not perform an authorization check when an actor attempts to access a resource or perform an action. Impacted is confidentiality. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-27454 since 02/19/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are known technical details, but no exploit is available.

Upgrading to version 2026.1.2 or 2026.2.1 eliminates this vulnerability. Applying the patch 8510fde30eb0d7f2dee822a95f6cf43b9ac943d0 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.2

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 5.3
CNA Vector (GitHub_M): 🔒

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Authorization
CWE: CWE-862 / CWE-863 / CWE-285
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Discourse 2026.1.2/2026.2.1
Patch: 8510fde30eb0d7f2dee822a95f6cf43b9ac943d0

Timelineinfo

02/19/2026 CVE reserved
03/20/2026 +29 days Advisory disclosed
03/20/2026 +0 days VulDB entry created
03/24/2026 +4 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-fq69-f929-wp96
Status: Confirmed

CVE: CVE-2026-27454 (🔒)
GCVE (CVE): GCVE-0-2026-27454
GCVE (VulDB): GCVE-100-351932

Entryinfo

Created: 03/20/2026 08:11
Updated: 03/24/2026 08:57
Changes: 03/20/2026 08:11 (67), 03/24/2026 08:57 (1)
Complete: 🔍
Cache ID: 216::103

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