| Name | CVE-2021-33503 |
| Description | An issue was discovered in urllib3 before 1.26.5. When provided with a URL containing many @ characters in the authority component, the authority regular expression exhibits catastrophic backtracking, causing a denial of service if a URL were passed as a parameter or redirected to via an HTTP redirect. |
| Source | CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
| Debian Bugs | 989848 |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|
| python-urllib3 (PTS) | buster | 1.24.1-1 | fixed |
| buster (security) | 1.24.1-1+deb10u2 | fixed |
| bullseye | 1.26.5-1~exp1 | fixed |
| bookworm | 1.26.12-1 | fixed |
| sid, trixie | 1.26.18-2 | fixed |
The information below is based on the following data on fixed versions.
Notes
[buster] - python-urllib3 <not-affected> (Vulnerable code introduced later)
[stretch] - python-urllib3 <not-affected> (Vulnerable code introduced later)
https://github.com/advisories/GHSA-q2q7-5pp4-w6pg
Introduced around: https://github.com/urllib3/urllib3/commit/5b047b645f5f93900d5e2fc31230848c25eb1f5f (1.25.4)
Fixed by: https://github.com/urllib3/urllib3/commit/2d4a3fee6de2fa45eb82169361918f759269b4ec (1.26.5)