CVE-2026-126189
Soup Sieve is a CSS selector library designed to be used with Beautiful Soup 4. Prior to 4.0.1, Soup Sieve repeatedly searches descendant subtrees for each candidate evaluated by :has() and repeatedly reevaluates a parent containing :has(> ...) for each child, causing quadratic matching on deeply nested or wide attacker-influenced HTML or XML. Applications using ordinary fixed selectors through select(), select_one(), or Beautiful Soup CSS APIs against untrusted documents can have a worker occupied for seconds or minutes, while applications that process only trusted documents are not affected. Selectors compiled with NOCACHE continue to use the old uncached behavior. This issue is fixed in version 4.0.1.
Properties
- Severity
- MEDIUM
- Nvd fetched at
- 2026-11-14T00:40:25.638091+00:00
- Epss score
- 0.00301
- Cvss severity
- MEDIUM
- Cvss score
- 5.3
- Retrieved at
- 2026-11-14T00:51:03+00:00
- Last source
- FIRST EPSS
- Score
- 5.3
- Cvss version
- 3.1
- Cve id
- CVE-2026-126189
- Cvss vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- First seen by Signal
- 2026-11-12T19:59:23+00:00
- Name
- CVE-2026-126189
- Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- Published at
- 2026-11-12T17:17:32.260
- Last modified
- 2026-11-12T19:09:06.967
- Epss percentile
- 0.23159
Related Entities (1)
HAS_WEAKNESS (1)
Related research
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