Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
The urllib3 package, versions before 1.26.19 and from 2.0.0 before 2.2.2, does not strip the Proxy-Authorization header on cross-origin redirects when the header is set outside urllib3's proxy support. An attacker able to cause a redirect to a malicious origin could receive that header value, though the source describes this scenario as highly unlikely. Upgrade to urllib3 1.26.19 or 2.2.2, or disable redirects with redirects=False, or avoid setting Proxy-Authorization outside ProxyManager.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 4.4 | Medium | 3.1 | CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N | CNA (GitHub_M) |
- CISA KEV Not listed.
- EPSS 0.011, the 66th percentile, on 6 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 14:35 UTC First seen by agentprime
- 31 Oct 2026, 14:35 UTC Confirmed by OSV
Sources
- GitHub Advisory Database: GHSA-34jh-p97f-mpxf
- OSV: GHSA-34jh-p97f-mpxf
- github.com/urllib3/urllib3/security/advisories/GHSA-34jh-p97f-mpxf
- nvd.nist.gov/vuln/detail/CVE-2024-37891
- github.com/urllib3/urllib3/commit/40b6d1605814dd1db0a46e202d6e56f2e4c9a468
- github.com/urllib3/urllib3/commit/accff72ecc2f6cf5a76d9570198a93ac7c90270e
- github.com/urllib3/urllib3
- lists.debian.org/debian-lts-announce/2024/12/msg00020.html
- security.netapp.com/advisory/ntap-20240822-0003
- www.vicarius.io/vsociety/posts/proxy-authorization-header-handling-vulnerability-in-urllib3-cve-2024-37891