CVE-2026-126193
Soup Sieve: Uncontrolled recursion in Soup Sieve CSS parser lets nested pseudo-class selectors exhaust the Python call stack
- Medium 5.3
Description
Soup Sieve is a CSS selector library for Beautiful Soup. From 0.4 until 3.0, deeply nested CSS pseudo-class selectors can cause recursive parsing to exceed Python’s recursion limit and raise RecursionError . Applications accepting untrusted selectors may experience failure of the affected request or task if the exception is not handled. The demonstrated behavior is recoverable and does not establish an interpreter crash or persistent service-wide denial of service. This vulnerability is fixed in version 3.0.
Key facts
- Published
- 12 Nov 2026
- Last changed
- 12 Nov 2026
- Assigned by
- GitHub_M
- EPSS
- 0.308% likely to be exploited in the next 30 days, higher than 23.894% of CVEs (scores for 15 Nov 2026)
Severity scores
Each score is shown as its source gave it. They are not averaged or merged.
- 5.3CVSS 3.1, Mediumfrom the CNA (GitHub_M)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Historical context and remediation
This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.
No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.
No explicit remediation statement is available on this page yet. Consult the original record and vendor references before choosing a fix.
Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.
Affected products
| Vendor | Product | Versions |
|---|---|---|
| facelessuser | soupsieve |
|
Timeline
- 12 Nov 2026 Published