Information disclosure in Discourse
CVE-2026-23743
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.
Vulnerability class: Information Disclosure
EPSS: 0.002 (15.8th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.
Affected products
- Discourse — versions >= 2026.1.0-latest, < 2026.1.0, >= 2025.12.0-latest, < 2025.12.1, < 3.5.4
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Third Party Advisory)
Frequently asked questions
- What is CVE-2026-23743?
- CVE-2026-23743 is a high-severity vulnerability in Discourse, classified under Information Disclosure. CVSS score: 7.5/10. Published 2026-01-28.
- How severe is CVE-2026-23743?
- High severity. CVSS v3 base score is 7.5 out of 10.