urllib3 redirects are not disabled when retries are disabled on PoolManager instantiation
urllib3 handles redirects and retries using the same mechanism, which is controlled by the Retry object. The most common way to disable redirects is at the request level, as follows:
resp = urllib3.request("GET", "https://httpbin.org/redirect/1", redirect=False)
print(resp.status)
# 302However, it is also possible to disable redirects, for all requests, by instantiating a PoolManager and specifying retries in a way that disable redirects:
import urllib3
http = urllib3.PoolManager(retries=0) # should raise MaxRetryError on redirect
http = urllib3.PoolManager(retries=urllib3.Retry(redirect=0)) # equivalent to the above
http = urllib3.PoolManager(retries=False) # should return the first response
resp = http.request("GET", "https://httpbin.org/redirect/1")However, the retries parameter is currently ignored, which means all the above examples don't disable redirects.
Affected usages
Passing retries on PoolManager instantiation to disable redirects or restrict their number.
By default, requests and botocore users are not affected.
Impact
Redirects are often used to exploit SSRF vulnerabilities. An application attempting to mitigate SSRF or open redirect vulnerabilities by disabling redirects at the PoolManager level will remain vulnerable.
Remediation
You can remediate this vulnerability with the following steps:
- Upgrade to a patched version of urllib3. If your organization would benefit from the continued support of urllib3 1.x, please contact sethmichaellarson@gmail.com to discuss sponsorship or contribution opportunities.
- Disable redirects at the
request()level instead of thePoolManager()level.
Software afectado
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| Plataforma | Paquete | Versiones vulnerables | Corregida en |
|---|---|---|---|
| Python (PyPI) | urllib3 | < 2.5.0 | 2.5.0 |
Referencias
- https://github.com/urllib3/urllib3/security/advisories/GHSA-pq67-6m6q-mj2v
- https://nvd.nist.gov/vuln/detail/CVE-2025-50181
- https://github.com/urllib3/urllib3/commit/f05b1329126d5be6de501f9d1e3e36738bc08857
- https://github.com/urllib3/urllib3
- https://github.com/urllib3/urllib3/releases/tag/2.5.0
- https://pypi.org/project/urllib3
- https://github.com/advisories/GHSA-pq67-6m6q-mj2v
- Vector CVSS
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N- Debilidad (CWE)
CWE-601- Plataforma
- Python (PyPI)
- Paquete
urllib3- Publicada
- 18.06.2025
- Actualizado
- 11.10.2026 15:17
Fuentes y licencias
OSV / GitHub Advisory Database - PYSEC-2026-1999 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-pq67-6m6q-mj2v - CC BY 4.0
Historial de vulnerabilidades: urllib3
Todas las vulnerabilidades publicadas de este paquete (Python (PyPI)), de la más reciente a la más antigua. Muestra si es un fallo aislado o un paquete que hay que vigilar.
- Entradas en total
- 22
- Primera → última
- 01.2017 09.2026
- Sin corrección
- 0
- Explotada en ataques
- 0
Distribución por gravedad
- Crítica 1
- Alta 11
- Media 10
Divulgaciones por año
- 2017: 1
- 2018: 1
- 2019: 2
- 2020: 2
- 2021: 2
- 2022: 0
- 2023: 3
- 2024: 1
- 2025: 4
- 2026: 6
-
urllib3 redirects are not disabled when retries are disabled on PoolManager instantiation esta entrada
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