CVE-2026-44432

Name	CVE-2026-44432
Description	urllib3 is an HTTP client library for Python. From 2.6.0 to before 2.7.0, urllib3 could decompress the whole response instead of the requested portion (1) during the second HTTPResponse.read(amt=N) call when the response was decompressed using the official Brotli library or (2) when HTTPResponse.drain_conn() was called after the response had been read and decompressed partially (compression algorithm did not matter here). These issues could cause urllib3 to fully decode a small amount of highly compressed data in a single operation. This could result in excessive resource consumption (high CPU usage and massive memory allocation for the decompressed data) on the client side. This vulnerability is fixed in 2.7.0.
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)
Debian Bugs	1136654

Vulnerable and fixed packages

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	vulnerable
	bookworm	1.26.12-1+deb12u1	fixed
	bookworm (security)	1.26.12-1+deb12u3	fixed
	trixie (security), trixie	2.3.0-3+deb13u1	fixed
	forky, sid	2.6.3-2	vulnerable

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Debian Bugs
python-urllib3	source	bookworm	(not affected)
python-urllib3	source	trixie	(not affected)
python-urllib3	source	(unstable)	(unfixed)	1136654

Notes

[trixie] - python-urllib3 <not-affected> (Vulnerable code introduced later)
[bookworm] - python-urllib3 <not-affected> (Vulnerable code introduced later)
https://github.com/urllib3/urllib3/security/advisories/GHSA-mf9v-mfxr-j63j