High 7.5Published Jul 14, 2026

CVE-2026-49477Soup Sieve: Regular Expression Denial of Service (ReDoS) in soupsieve Selector Parser

Updated under an hour ago (Oct 26, 2026, 4:30 PM ET)

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It affects facelessuser soupsieve and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for facelessuser soupsieve

Exploited in the last 30 days

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: 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-400, CWE-1333
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Jul 21, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

facelessuser soupsieve facelessuser:soupsieve (from the name)	before 2.8.4	CNA record
facelessuser soup_sieve facelessuser:soup_sieve	before 2.8.4	NVD

References

References

https://github.com/facelessuser/soupsieve/security/advisories/GHSA-836r-79rf-4m37	x-refsource-confirm, exploit, vendor-advisory
https://github.com/facelessuser/soupsieve/commit/eb4397618709186c109400448c6043b728217dc3	x-refsource-misc, patch
https://github.com/facelessuser/soupsieve/releases/tag/2.8.4	x-refsource-misc, release-notes

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.