CVE-2026-49477

Name	CVE-2026-49477
Description	Soup Sieve is a CSS selector library designed to be used with Beautiful Soup 4. Prior to 2.8.4, the CSS selector parser in soupsieve contains a regular expression vulnerable to catastrophic backtracking when processing an attribute selector with an unterminated quoted value in soupsieve/css_parser.py, allowing an attacker who can supply untrusted CSS selector strings to soupsieve.compile() or Beautiful Soup .select() / .select_one() to cause CPU exhaustion and denial of service. This issue is fixed in version 2.8.4.
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)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
soupsieve (PTS)	bullseye	2.2.1-1	vulnerable
	bookworm	2.3.2-1	vulnerable
	trixie	2.7-1	vulnerable
	forky, sid	2.8.4-1	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
soupsieve	source	(unstable)	2.8.4-1

Notes

https://github.com/facelessuser/soupsieve/security/advisories/GHSA-836r-79rf-4m37
Fixed by: https://github.com/facelessuser/soupsieve/commit/eb4397618709186c109400448c6043b728217dc3 (2.8.4)