CVE-2026-49476

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

HIGH
7.5
CVSS Score
Published: July 14, 2026 at 08:53 PM UTC
Updated: October 24, 2026 at 09:10 PM UTC
1 product affected across 1 vendorSoup Sieve

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Severity
HIGH7.5
Exploit prediction
EPSS 0.6%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 2.8.4
Affected range stops below 2.8.4, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (3)

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-400CWE-770

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