| Name | CVE-2025-66418 |
| Description | urllib3 is a user-friendly HTTP client library for Python. Starting in version 1.24 and prior to 2.6.0, the number of links in the decompression chain was unbounded allowing a malicious server to insert a virtually unlimited number of compression steps leading to high CPU usage and massive memory allocation for the decompressed data. This vulnerability is fixed in 2.6.0. |
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
| References | DLA-4421-1, DSA-6102-1 |
| Debian Bugs | 1122030 |
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| python-urllib3 (PTS) | bullseye | 1.26.5-1~exp1 | vulnerable |
| bullseye (security) | 1.26.5-1~exp1+deb11u3 | fixed | |
| bookworm | 1.26.12-1+deb12u1 | vulnerable | |
| bookworm (security) | 1.26.12-1+deb12u3 | fixed | |
| trixie | 2.3.0-3 | vulnerable | |
| trixie (security) | 2.3.0-3+deb13u1 | fixed | |
| forky, sid | 2.5.0-2 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| python-urllib3 | source | bullseye | 1.26.5-1~exp1+deb11u2 | DLA-4421-1 | ||
| python-urllib3 | source | bookworm | 1.26.12-1+deb12u2 | DSA-6102-1 | ||
| python-urllib3 | source | trixie | 2.3.0-3+deb13u1 | DSA-6102-1 | ||
| python-urllib3 | source | (unstable) | 2.5.0-1.1 | 1122030 |
https://www.openwall.com/lists/oss-security/2025/12/05/4
https://github.com/urllib3/urllib3/security/advisories/GHSA-gm62-xv2j-4w53
Fixed by: https://github.com/urllib3/urllib3/commit/24d7b67eac89f94e11003424bcf0d8f7b72222a8 (2.6.0)