urllib3 does not control redirects in browsers and Node.js

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.3 · CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

EPSS

• CVE-2025-50182: 0.60% estimated exploitation activity in the next 30 days; percentile 48.84 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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…

Published by the source

18 Jun 2025, 17:50 UTC

Last modified by the source

10 Sep 2026, 03:50 UTC

Source last checked

26 Oct 2026, 13:36 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-48p4-8xcf-vxj5

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-48p4-8xcf-vxj5

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# Patch Next advisory brief: CVE-2025-50182

Advisory: urllib3 does not control redirects in browsers and Node.js
IDs: CVE-2025-50182, GHSA-48p4-8xcf-vxj5
Record: https://patchnext.com/advisories/cve-2025-50182 (revision 2, source checked 26 Oct 2026, 13:36 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: urllib3 2.5.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI urllib3: affected >= 2.2.0, < 2.5.0; fixed in 2.5.0

## Suggested inspection (read-only)
- `python -m pip show urllib3`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on urllib3.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-48p4-8xcf-vxj5 (OSV record GHSA-48p4-8xcf-vxj5 lists affected ranges: PyPI urllib3 >=2.2.0 <2.5.0 (fixed))
- Verified: https://github.com/advisories/GHSA-48p4-8xcf-vxj5 (GitHub-reviewed advisory GHSA-48p4-8xcf-vxj5 lists affected ranges: PyPI urllib3 >=2.2.0 <2.5.0)

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