Discourse: Don't leak restricted tag group names via tag info

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Summary

CVECVE-2026-47264
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-06-12 21:16:23 UTC
Updated2026-06-17 18:40:35 UTC
DescriptionDiscourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.4, 2026.3.0-latest to before 2026.3.1, and 2026.4.0-latest to before 2026.4.1, DetailedTagSerializer#tag_group_names returned every tag group a tag belonged to without filtering against the requesting user's visibility. With SiteSetting.tags_listed_by_group enabled, anonymous and unprivileged users hitting TagsController#info (which is exempt from requires_login) could read the names of tag groups restricted to specific user groups or non-visible categories. This issue has been patched in versions 2026.1.4, 2026.3.1, 2026.4.1, and 2026.5.0-latest.1.

Risk And Classification

Primary CVSS: v3.1 5.3 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS: 0.002160000 probability, percentile 0.117810000 (date 2026-06-22)

Problem Types: CWE-200 | CWE-200 CWE-200: Exposure of Sensitive Information to an Unauthorized Actor

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
3.1CNADECLARED5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Discourse Discourse All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Discourse Discourse affected >= 2026.1.0-latest, < 2026.1.4 Not specified
CNA Discourse Discourse affected >= 2026.3.0-latest, < 2026.3.1 Not specified
CNA Discourse Discourse affected >= 2026.4.0-latest, < 2026.4.1 Not specified

References

ReferenceSourceLinkTags
github.com/discourse/discourse/security/advisories/GHSA-4q5q-6hh6-53x2 [email protected] github.com Third Party Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis
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