CVE-2026-52783: Opf Openproject

High severity, CVSS 8.2. EPSS: 0.2% chance of exploitation in the next 30 days.

OpenProject is open-source, web-based project management software. Prior to 17.3.3 and 17.4.1, OpenProject's Storages module writes the OneDrive/SharePoint userless OAuth access_token plaintext to Rails.cache under the deterministic key storage.<id>.httpx_access_token, repopulated continuously by an hourly cron and every userless-OAuth call site (see Write cadence). None of the three allowed cache backends (file_store, memcache, redis) encrypts at rest. An attacker with read access to the cache backend recovers the Azure-AD application-tier bearer with an anonymous get over the memcached binary protocol (or the equivalent against Redis). This vulnerability is fixed in 17.3.3 and 17.4.1.

Affected products

• Opf Openproject: before 17.3.3 (fixed in 17.3.3); from 17.4.0, before 17.4.1 (fixed in 17.4.1)

Published 2026-06-26. Last modified 2026-06-29.