GHSA-pq67-6m6q-mj2v urllib3 redirects are not disabled when retries are disabled on PoolManager instantiation

• PyPI urllib3: < 2.5.0 → fixed in 2.5.0

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 [email protected] to discuss sponsorship or contribution opportunities. • Disable redirects at the `request()` level instead of the `PoolManager()` level.