CVE-2025-50181: Urllib3 Urllib3 Redirects Are Not Disabled Vulnerability

MODERATE
Advisory Identifier: GHSA-pq67-6m6q-mj2v
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CVSS 5.3
CWE-601
Published
Advisory Summary

CVE-2025-50181 is a MODERATE (CVSS 5.3) urllib3 redirects are not disabled vulnerability (CWE-601: URL Redirection to Untrusted Site ('Open Redirect')) affecting Urllib3 libraries in the PyPI ecosystem. The issue involves urllib3 redirects are not disabled when retries are disabled on poolmanager instantiation. Remediation is available by upgrading affected packages to version 2.5.0.

CVE-2025-50181 at a Glance

CVE Identifier CVE-2025-50181
GHSA Identifier GHSA-pq67-6m6q-mj2v
Severity MODERATE
CVSS v3.1 Base Score 5.3
CWE Classification CWE-601: URL Redirection to Untrusted Site ('Open Redirect')
Affected Product Urllib3
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 5.3

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity None (I:N)
Availability None (A:N)

How to Fix CVE-2025-50181

To remediate this vulnerability, upgrade all affected Urllib3 dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

urllib3 fixed: 2.5.0 
pip install urllib3>=2.5.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show urllib3

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2025-50181, inspect your installed packages using pip:

pip show urllib3

Analyze the terminal output to locate any version of Urllib3 in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.5.0), your application is affected.

Note: The pip show urllib3 command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-601: URL Redirection to Untrusted Site ('Open Redirect'), where the web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect. In Urllib3, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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: ```python resp = urllib3.request("GET", "https://httpbin.org/redirect/1", redirect=False) print(resp.status) # 302 ``` However, it is also possible to disable redirects, for all requests, by instantiating a `PoolManager` and specifying `retries` in a way that disable redirects: ```python 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](mailto:sethmichaellarson@gmail.com) to discuss sponsorship or contribution opportunities. * Disable redirects at the `request()` level instead of the `PoolManager()` level.

CVE-2025-50181 Affected Urllib3 Versions

1 component(s)
Fixed Versions:
2.5.0
Product / Package Ecosystem Affected Versions Fixed Version
urllib3
pypi/urllib3
PyPI
< 2.5.0
2.5.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/urllib3/urllib3/security/advisories/GHSA-pq67-6m6q-mj2v
NVD — CVE-2025-50181 NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-50181
Security Fix Commit FIX COMMIT
https://github.com/urllib3/urllib3/commit/f05b1329126d5be6de501f9d1e3e36738bc08857
Urllib3 Source Repository REPOSITORY
https://github.com/urllib3/urllib3
Urllib3 Release RELEASE
https://github.com/urllib3/urllib3/releases/tag/2.5.0

Frequently Asked Questions

What is CVE-2025-50181?
CVE-2025-50181 is a security vulnerability in Urllib3 involving urllib3 redirects are not disabled when retries are disabled on PoolManager instantiation under CWE-601: URL Redirection to Untrusted Site ('Open Redirect').
Which Urllib3 versions are affected?
Affected versions include releases prior to 2.5.0 across affected packages: urllib3.
What version fixes CVE-2025-50181?
Upgrading to 2.5.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is urllib3 affected?
Yes, urllib3 is affected in releases prior to 2.5.0. Upgrade your dependency to 2.5.0 or later.
What is the CVSS score of CVE-2025-50181?
CVE-2025-50181 has a CVSS v3.1 base score of 5.3 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N.
What CWE is associated with CVE-2025-50181?
CVE-2025-50181 is classified under CWE-601: URL Redirection to Untrusted Site ('Open Redirect') (The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.).
How can I check PyPI dependencies for CVE-2025-50181?
Run the dependency tree command: 'pip show urllib3'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-pq67-6m6q-mj2v",
  "modified" : "2025-12-22T21:33:21Z",
  "published" : "2025-06-18T17:50:00Z",
  "aliases" : [ "CVE-2025-50181" ],
  "summary" : "urllib3 redirects are not disabled when retries are disabled on PoolManager instantiation",
  "details" : "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:\n\n```python\nresp = urllib3.request(\"GET\", \"https://httpbin.org/redirect/1\", redirect=False)\nprint(resp.status)\n# 302\n```\n\nHowever, it is also possible to disable redirects, for all requests, by instantiating a `PoolManager` and specifying `retries` in a way that disable redirects:\n\n```python\nimport urllib3\n\nhttp = urllib3.PoolManager(retries=0)  # should raise MaxRetryError on redirect\nhttp = urllib3.PoolManager(retries=urllib3.Retry(redirect=0))  # equivalent to the above\nhttp = urllib3.PoolManager(retries=False)  # should return the first response\n\nresp = http.request(\"GET\", \"https://httpbin.org/redirect/1\")\n```\n\nHowever, the `retries` parameter is currently ignored, which means all the above examples don't disable redirects.\n\n## Affected usages\n\nPassing `retries` on `PoolManager` instantiation to disable redirects or restrict their number.\n\nBy default, requests and botocore users are not affected.\n\n## Impact\n\nRedirects 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.\n\n## Remediation\n\nYou can remediate this vulnerability with the following steps:\n\n * 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](mailto:sethmichaellarson@gmail.com) to discuss sponsorship or contribution opportunities.\n * Disable redirects at the `request()` level instead of the `PoolManager()` level.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "urllib3"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.5.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/urllib3/urllib3/security/advisories/GHSA-pq67-6m6q-mj2v"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-50181"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/urllib3/urllib3/commit/f05b1329126d5be6de501f9d1e3e36738bc08857"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/urllib3/urllib3"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/urllib3/urllib3/releases/tag/2.5.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-601" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-06-18T17:50:00Z",
    "nvd_published_at" : "2025-06-19T01:15:24Z"
  }
}