Vulnerability in Opf Openproject

CVE-2026-52783

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.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.002 (8.8th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 9th percentile — 8.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-52783: held from 0.002 to 0.002.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-52783?
CVE-2026-52783 is a high-severity vulnerability in Opf Openproject, classified under Cleartext Storage in a File or on Disk. CVSS score: 8.2/10. Published 2026-06-26.
How severe is CVE-2026-52783?
High severity. CVSS v3 base score is 8.2 out of 10.