CVE-2026-49477: high-severity vulnerability in facelessuser soupsieve
Soup Sieve: Regular Expression Denial of Service (ReDoS) in soupsieve Selector Parser
Published · Updated
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.5epss 0.6%
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
facelessuser · soupsieveRelated CVEs — facelessuser soupsieve
In the same product, most dangerous first.
CVE-2026-49476HIGHSoup Sieve: Memory Exhaustion via Large Comma-Separated Selector Lists in soupsieveEPSS 0.6%CVE-2026-85999MEDIUMSoup Sieve: Polynomial-time ReDoS (O(n²)) in the whitespace/comment trimming regex `RE_WS_END` (triggers on VALID selectors)EPSS 0.6%CVE-2026-86000MEDIUMSoup Sieve: Polynomial-time ReDoS (O(n²)) in the `IDENTIFIER` / `VALUE` selector sub-patternsEPSS 0.6%