CVE-2026-49477
Soup Sieve: Regular Expression Denial of Service (ReDoS) in soupsieve Selector Parser
HIGH 7.5
At a glance
- Source
- NVD
- EPSS
- EPSS 0.64 % · percentile 51 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- 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.
Weaknesses (CWE)
- CWE-400 — Uncontrolled Resource Consumption (DoS)
- CWE-1333 — Inefficient Regular Expression Complexity (ReDoS)
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | GitHub_M |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | NVD · security-advisories@github.com (Secondary) |
Advisories
- GHSA-836r-79rf-4m37 — Soup Sieve: Regular Expression Denial of Service (ReDoS) via Selector Parser
- PYSEC-2026-3072 — Soup Sieve: Regular Expression Denial of Service (ReDoS) via Selector Parser
European references
- ENISA EUVD · EUVD-2026-44538
- GCVE · GCVE-0-2026-49477
CERT-FR advisories
- CERTFR-2026-AVI-1206 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1094 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:facelessuser:soup_sieve:*:*:*:*:*:beautiful_soup:*:*< 2.8.4
Affected products
| Product | Versions |
|---|---|
| facelessuser · soupsieve | affected < 2.8.4 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |