CVE-2026-23743

Discourse allows permalinks to restricted resources to leak resource slugs to unauthorized users

State: Published
Severity: 6.9 Medium
Published: Jan 28, 2026
Updated: Jan 28, 2026
Reserved: Jan 15, 2026

Description

Discourse is an open source discussion platform. In versions prior to 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0, permalinks pointing to access-restricted resources (private topics, categories, posts, or hidden tags) were redirecting users to URLs containing the resource slug, even when the user didn't have access to view the resource. This leaked potentially sensitive information (e.g., private topic titles) via the redirect Location header and the 404 page's search box. This issue is patched in versions 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0. No known workarounds are available.

Scores

CVSS	Score	Vector	Source
4.0	6.9 Medium	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N	GitHub_M

Weaknesses

CWE-200 Exposure of Sensitive Information to an Unauthorized Actor

Affected Products

Product	Versions
discoursediscourse	< 3.5.4Affected >= 2025.11.0-latest, < 2025.11.2Affected >= 2025.12.0-latest, < 2025.12.1Affected >= 2026.1.0-latest, < 2026.1.0Affected

References

https://github.com/discourse/discourse/security/advisories/GHSA-v5jw-rxc6-4cvv

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