XSS in Cern Rucio
CVE-2026-25734
Rucio is a software framework that provides functionality to organize, manage, and access large volumes of scientific data using customizable policies. Versions prior to 35.8.3, 38.5.4, and 39.3.1 have a stored Cross-Site Scripting (XSS) vulnerability in the RSE metadata of the WebUI where attacker-controlled input is persisted by the backend and later rendered in the WebUI without proper output encoding. This allows arbitrary JavaScript execution in the context of the WebUI for users who view affected pages, potentially enabling session token theft or unauthorized actions. Versions 35.8.3, 38.5.4, and 39.3.1 fix the issue.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.005 (39.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 39th percentile — 39.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.002
Affected products
- Cern Rucio
- Rucio — versions < 35.8.3, >= 36.0.0rc1, < 38.5.4, >= 39.0.0rc1, < 39.3.1
Weakness classification (CWE)
References
- github.com/rucio/rucio/security/advisories/GHSA-h9fp-p2p9-873q (Exploit, Vendor Advisory)
- cheatsheetseries.owasp.org/cheatsheets/Cross_Site_Scripting_Prevention_Cheat_Sh… (Not Applicable)
- github.com/rucio/rucio/releases/tag/35.8.3 (Product, Release Notes)
- github.com/rucio/rucio/releases/tag/38.5.4 (Product, Release Notes)
- github.com/rucio/rucio/releases/tag/39.3.1 (Product, Release Notes)
Frequently asked questions
- What is CVE-2026-25734?
- CVE-2026-25734 is a medium-severity vulnerability in Cern Rucio, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-02-25.
- How severe is CVE-2026-25734?
- Medium severity. CVSS v3 base score is 6.1 out of 10.