CVE-2026-49477 — Security Box Score

CVE · referencelatest edition

Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-49477HIGH

facelessuser soupsieve — Soup Sieve: Regular Expression Denial of Service (ReDoS) in soupsieve Selector Parser

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   L   N   N  U  N  N  H    7.5   .0052   42.1     —

AFFECTED
  Product    Versions   Fixed
  soupsieve  < 2.8.4 –  —

TIMELINE
  May 30  Reserved by GitHub_M
  Jul 14  EXPLOIT PUBLISHED — CVE-2026-49477 (facelessuser soupsieve). Public exploit reference added.
  Jul 14  Published (CNA: GitHub_M)
  Jul 28  EXPLOIT PUBLISHED — CVE-2026-49477 (facelessuser soupsieve). Public exploit reference added.

CWE-400, CWE-1333 · CNA: GitHub_M · CVSS v3.1 · 3 references · NVD status: Analyzed

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 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.

Lifecycle

Complete event history — 4 events, chronological
Date	Event	Detail
May 30, 2026	Reserved	Reserved by GitHub_M
July 14, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-49477 (facelessuser soupsieve). Public exploit reference added.
July 14, 2026	Published	Published (CNA: GitHub_M)
July 28, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-49477 (facelessuser soupsieve). Public exploit reference added.

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
facelessuser	soupsieve	—	< 2.8.4	—

Weaknesses

CWE-400 · CWE-1333

References (3)

https://github.com/facelessuser/soupsieve/commit/eb4397618709186c109400448c6043b728217dc3 [Patch]
https://github.com/facelessuser/soupsieve/releases/tag/2.8.4 [Release Notes]
https://github.com/facelessuser/soupsieve/security/advisories/GHSA-836r-79rf-4m37 [Exploit, Vendor Advisory]

Authoritative record: CVE-2026-49477 at cve.org

Vendors: facelessuser

Weaknesses: CWE-400 · CWE-1333

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-49477 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.