CVE-2025-68934: Discourse

Medium severity, CVSS 6.5. EPSS: 0.3% chance of exploitation in the next 30 days.

Discourse is an open source discussion platform. In versions prior to 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0, authenticated users can submit crafted payloads to /drafts.json that cause O(n^2) processing in Base62.decode, tying up workers for 35-60 seconds per request. This affects all users as the shared worker pool becomes exhausted. This issue is patched in versions 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0. Lowering the max_draft_length site setting reduces attack surface but does not fully mitigate the issue, as payloads under the limit can still trigger the slow code path.

Affected products

• Discourse Discourse: before 3.5.4 (fixed in 3.5.4); from 2025.11.0, before 2025.11.2 (fixed in 2025.11.2); version 2025.12.0 only; version 2026.1.0 only

Published 2026-01-28. Last modified 2026-06-17.