Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, restricted tag and tag-group names attached to publicly readable categories as allowed_tags, allowed_tag_groups, or required tag groups could leak to anonymous and unauthorized users through category and group endpoints. This issue is fixed in versions 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements Present

User Interaction None

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
discourse discourse affected
Version Status Constraints
>= 2026.1.0-latest, < 2026.1.5 affected —
>= 2026.4.0-latest, < 2026.4.2 affected —
>= 2026.5.0-latest, < 2026.5.1 affected —

No data.

No data.

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Vendors Products
Discourse Subscribe
Discourse Subscribe

Project Subscriptions

Vendors Products
Discourse Subscribe
Discourse Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/discourse/discourse/releases/tag/v2026.1.5 cve-icon
https://github.com/discourse/discourse/releases/tag/v2026.4.2 cve-icon
https://github.com/discourse/discourse/releases/tag/v2026.5.1 cve-icon
https://github.com/discourse/discourse/releases/tag/v2026.6.0 cve-icon
https://github.com/discourse/discourse/security/advisories/GHSA-mwp7-572g-6qpx cve-icon
History

Fri, 10 Jul 2026 00:00:00 +0000

Type Values Removed Values Added
First Time appeared Discourse
Discourse discourse
Vendors & Products Discourse
Discourse discourse

Thu, 09 Jul 2026 22:15:00 +0000

Type Values Removed Values Added
Description Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, restricted tag and tag-group names attached to publicly readable categories as allowed_tags, allowed_tag_groups, or required tag groups could leak to anonymous and unauthorized users through category and group endpoints. This issue is fixed in versions 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5.
Title Discourse: Hidden tag names leaked via category serializers
Weaknesses CWE-200
References
Metrics cvssV4_0

{'score': 6.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-07-09T21:56:40.444Z

Reserved: 2026-05-28T14:33:01.179Z

Link: CVE-2026-49256

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-07-09T23:45:03Z

Weaknesses