CVE-2026-49476

Soup Sieve: Memory Exhaustion via Large Comma-Separated Selector Lists in soupsieve

Published Jul 14, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
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 allocates unbounded memory when compiling large comma-separated selector lists, allowing an attacker who can supply a crafted selector string to soupsieve.compile() or Beautiful Soup .select() / .select_one() to allocate hundreds of megabytes of heap memory from a relatively small input and cause denial of service. This issue is fixed in version 2.8.4.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-2wc2-fm75-p42x Soup Sieve has Memory Exhaustion via Large Comma-Separated Selector Lists
History
Type Values Removed Values Added
First Time appeared Facelessuser
Facelessuser soupsieve
Vendors & Products Facelessuser
Facelessuser soupsieve
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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 allocates unbounded memory when compiling large comma-separated selector lists, allowing an attacker who can supply a crafted selector string to soupsieve.compile() or Beautiful Soup .select() / .select_one() to allocate hundreds of megabytes of heap memory from a relatively small input and cause denial of service. This issue is fixed in version 2.8.4.
Title Soup Sieve: Memory Exhaustion via Large Comma-Separated Selector Lists in soupsieve
Weaknesses CWE-400
CWE-770
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Jul 15, 2026, 2:27 PM
Reserved
May 30, 2026, 4:17 AM
Status
Analyzed
Published
Jul 14, 2026, 9:17 PM
Modified
Oct 24, 2026, 9:10 PM
Severity
Important
Public date
Jul 14, 2026, 8:53 PM