# CVE-2025-50182: urllib3 does not control redirects in browsers and Node.js

> urllib3 fails to enforce redirect controls in Pyodide environments, allowing attackers to bypass redirect restrictions in browser or Node.js contexts.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Jun 2025
- **Updated:** 22 Dec 2025
- **Also known as:** BELL-CVE-2025-50182, DEBIAN-CVE-2025-50182, ECHO-3380-b531-9695, GHSA-48p4-8xcf-vxj5, MINI-2xp2-hhm7-7x36, MINI-33pg-98jg-5x3q, MINI-cw43-9g4j-7qfj, MINI-fxx6-6gfc-q5pv, MINI-r6mx-wf87-j772, MINI-x5xw-x889-9w7w, PYSEC-2026-1997, ROOT-APP-PYPI-CVE-2025-50182

## What is CVE-2025-50182?

CVE-2025-50182 is a medium-severity vulnerability in urllib3, published on 19 Jun 2025. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

urllib3 is a user-friendly HTTP client library for Python. Starting in version 2.2.0 and prior to 2.5.0, urllib3 does not control redirects in browsers and Node.js. urllib3 supports being used in a Pyodide runtime utilizing the JavaScript Fetch API or falling back on XMLHttpRequest. This means Python libraries can be used to make HTTP requests from a browser or Node.js. Additionally, urllib3 provides a mechanism to control redirects, but the retries and redirect parameters are ignored with Pyodide; the runtime itself determines redirect behavior. This issue has been patched in version 2.5.0.

Weakness: CWE-601 (URL Redirection to Untrusted Site)

## Which versions are affected by CVE-2025-50182?

3 open source packages ship an affected version, including urllib3. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `urllib3` | PyPI | From 2.2.0 | 2.5.0 |
| `urllib3` | PyPI | From 2.2.0 | 2.5.0 |
| `urllib3` | PyPI | From 2.2.0 | 2.5.0 |

Products: Python Urllib3.

## How do I fix CVE-2025-50182?

Upgrade urllib3 to 2.5.0 or later.

## Is CVE-2025-50182 being exploited?

There is no known exploitation of CVE-2025-50182 in the wild and no public exploit code.

## Other vulnerabilities in urllib3

- [CVE-2026-97689](https://insights.sbomify.com/CVE-2026-97689/): urllib3: HTTPResponse.stream()/read_chunked() buffers an unbounded chunk-size line into memory (high 8.9)
- [CVE-2026-44432](https://insights.sbomify.com/CVE-2026-44432/): urllib3: Decompression-bomb safeguards bypassed in parts of the streaming API (high 8.9)
- [CVE-2026-21441](https://insights.sbomify.com/CVE-2026-21441/): urllib3 vulnerable to decompression-bomb safeguard bypass when following HTTP redirects (streaming API) (high 8.9)
- [CVE-2025-66418](https://insights.sbomify.com/CVE-2025-66418/): urllib3 allows an unbounded number of links in the decompression chain (high 8.9)
- [CVE-2025-66471](https://insights.sbomify.com/CVE-2025-66471/): urllib3 Streaming API improperly handles highly compressed data (high 8.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-50182 and fix it if it is affected.

What it is: CVE-2025-50182 is a medium-severity vulnerability in urllib3, published on 19 Jun 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-50182 in the wild and no public exploit code.

Affected packages and fixed versions:
- urllib3 (PyPI): affected from 2.2.0; fixed in 2.5.0
- urllib3 (PyPI): affected from 2.2.0; fixed in 2.5.0
- urllib3 (PyPI): affected from 2.2.0; fixed in 2.5.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-50182/ (Markdown: https://insights.sbomify.com/CVE-2025-50182/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-50182
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-50182
- OSV: https://osv.dev/vulnerability/CVE-2025-50182

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-50182/
Summaries are generated and may contain mistakes; the official description above is the record.