CVE-2026-25136
HIGHCVE-2026-25136 is a high-severity (CVSS 8.1) Cross-site Scripting (XSS) vulnerability in rucio-webui. O3 Security confirms whether CVE-2026-25136 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Rucio WebUI has a Reflected Cross-site Scripting Vulnerability
Blast Radius
rucio-webui🐍rucio-webui🐍rucio-webuiReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Rucio is a software framework that provides functionality to organize, manage, and access large volumes of scientific data using customizable policies. A reflected Cross-site Scripting vulnerability was located in versions prior to 35.8.3, 38.5.4, and 39.3.1 in the rendering of the ExceptionMessage of the WebUI 500 error which could allow attackers to steal login session tokens of users who navigate to a specially crafted URL. Versions 35.8.3, 38.5.4, and 39.3.1 fix the issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | rucio-webui | all versions | 35.8.3 |
| 🐍PyPI | rucio-webui | ≥ 36.0.0rc1&&< 38.5.4 | 38.5.4 |
| 🐍PyPI | rucio-webui | ≥ 39.0.0rc1&&< 39.3.1 | 39.3.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for rucio-webui. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update rucio-webui to 35.8.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-25136 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-25136 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-25136. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-25136 in your dependencies?
O3 detects CVE-2026-25136 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.