CVE-2026-23743

Summary

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.

Affected Software

VendorProductVersion RangeStatus
discoursediscourse< 3.5.4affected
discoursediscourse>= 2025.11.0-latest, < 2025.11.2affected
discoursediscourse>= 2025.12.0-latest, < 2025.12.1affected
discoursediscourse>= 2026.1.0-latest, < 2026.1.0affected

Weaknesses

  • CWE-200: CWE-200: Exposure of Sensitive Information to an Unauthorized Actor

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: yes
    • Technical Impact: partial

References