CVE-2026-49477Public exploitNetwork attack vectorHinoki check available

Service interruption via catastrophic selector backtracking

Published Jul 14, 2026 · Updated Jul 14, 2026

ReDoS in facelessuser Soup Sieve before 2.8.4 allows remote attackers to hang applications via untrusted CSS selectors. The VALUE pattern in soupsieve/css_parser.py permits overlapping branches to backtrack exponentially on an unterminated quoted attribute value. Exposure requires an application to pass attacker-controlled selectors to soupsieve.compile() or Beautiful Soup select APIs; CPU exhaustion then blocks workers and interrupts service.

CVSS severity7.5
High
EPSS probability0.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

ReDoS in facelessuser Soup Sieve before 2.8.4 allows remote attackers to hang applications via untrusted CSS selectors. The VALUE pattern in soupsieve/css_parser.py permits overlapping branches to backtrack exponentially on an unterminated quoted attribute value. Exposure requires an application to pass attacker-controlled selectors to soupsieve.compile() or Beautiful Soup select APIs; CPU exhaustion then blocks workers and interrupts service.

The record

CVE
CVE-2026-49477
Published
Jul 14, 2026
Updated
Jul 14, 2026
Vendor
facelessuser
Product
Soup Sieve
Classifications
CWE-400, CWE-1333, T1499.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2.8.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

facelessuser · Soup Sieveversion=< 2.8.4

Published CVSS scores

7.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
CWE-1333Inefficient Regular Expression Complexity
T1499.002Service Exhaustion

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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