GHSA-pq67-6m6q-mj2v
urllib3 redirects are not disabled when retries are disabled on PoolManager instantiation
Packages
Details
As written in the advisory (Markdown source, shown as plain text).
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]](mailto:[email protected]) to discuss sponsorship or contribution opportunities.
* Disable redirects at the `request()` level instead of the `PoolManager()` level.
References
External links from the advisory. They lead to third-party sites.