GHSA-48p4-8xcf-vxj5
MEDIUMurllib3 does not control redirects in browsers and Node.js
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
urllib3Real-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
urllib3 supports being used in a Pyodide runtime utilizing the JavaScript Fetch API or falling back on XMLHttpRequest. This means you can use Python libraries to make HTTP requests from your browser or Node.js. Additionally, urllib3 provides a mechanism to control redirects.
However, the retries and redirect parameters are ignored with Pyodide; the runtime itself determines redirect behavior.
Affected usages
Any code which relies on urllib3 to control the number of redirects for an HTTP request in a Pyodide runtime.
Impact
Redirects are often used to exploit SSRF vulnerabilities. An application attempting to mitigate SSRF or open redirect vulnerabilities by disabling redirects may remain vulnerable if a Pyodide runtime redirect mechanism is unsuitable.
Remediation
If you use urllib3 in Node.js, upgrade to a patched version of urllib3.
Unfortunately, browsers provide no suitable way which urllib3 can use: XMLHttpRequest provides no control over redirects, the Fetch API returns opaqueredirect responses lacking data when redirects are controlled manually. Expect default browser behavior for redirects.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | urllib3 | ≥ 2.2.0&&< 2.5.0 | 2.5.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for urllib3. 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 urllib3 to 2.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-48p4-8xcf-vxj5 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 GHSA-48p4-8xcf-vxj5 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 GHSA-48p4-8xcf-vxj5. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-48p4-8xcf-vxj5 in your dependencies?
O3 detects GHSA-48p4-8xcf-vxj5 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.