High severity · published Jan 28, 2026
CVE-2026-23743
Discourse allows permalinks to restricted resources to leak resource slugs to unauthorized users
7.5
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 22% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
DI
discourse · discourse
< 3.5.4; >= 2025.11.0-latest, < 2025.11.2; >= 2025.12.0-latest, < 2025.12.1; >= 2026.1.0-latest, < 2026.1.0 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-23743
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-23743
Third Party Advisory
https://github.com/discourse/discourse/security/advisories/GHSA-v5jw-rxc6-4cvv
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