CVE-2021-25963 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in shuup. O3 Security confirms whether CVE-2021-25963 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Cross-site Scripting in shuup
Real-World Exposure
shuupReal-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
In Shuup, versions 1.6.0 through 2.10.8 are vulnerable to reflected Cross-Site Scripting (XSS) that allows execution of arbitrary javascript code on a victim browser. This vulnerability exists due to the error page contents not escaped.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | shuup | ≥ 1.6.0&&< 2.11.0 | 2.11.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for shuup. 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 shuup to 2.11.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-25963 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-2021-25963 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-2021-25963. 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-2021-25963 in your dependencies?
O3 detects CVE-2021-25963 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.