CVSS 3.1
5.3 mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:LCVE-2026-126193 Soup Sieve: Uncontrolled recursion in Soup Sieve CSS parser lets nested pseudo-class selectors exhaust the Python call stack
Medium (5.3) in facelessuser soupsieve. EPSS 0.3% estimated probability of exploitation activity in the next 30 days. Fixed in soupsieve 3.0.2.
On this page
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.
Severity
- EPSS
- 0.3% estimated probability of exploitation activity in the next 30 days; 24th percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
- CWE
- CWE-674 Uncontrolled Recursion
- Published
- Modified
- Assigned by
- GitHub_M (CNA)
- NVD analysis
- Awaiting analysis
- Record from
- the NVD, synced
Ask an AI about this CVE
Show the prompt
Explain CVE-2026-126193 for an engineer deciding whether to act. Use https://cve.bz/api/public/cves/CVE-2026-126193?via=ask-ai-copy and https://cve.bz/cve/CVE-2026-126193?via=ask-ai-copy as the source of truth: what is affected and which versions fix it, whether it is in CISA KEV, public exploits, and its EPSS (an internet-wide 30-day estimate of exploitation activity, not a forecast for my systems). If they give no fixed versions, use the CVE record https://cveawg.mitre.org/api/cve/CVE-2026-126193 or the vendor advisory, not third-party mirrors. Tell me how to check whether I am affected and how to verify a fix. Cite the sources and say where they are uncertain.Opens a third-party assistant; its answer is its own, not cve.bz's. The prompt holds only this CVE's id and public links.
Badge for a README or a site
An image that stays current: it is drawn from the data each time it is fetched (a host that proxies images, as GitHub does, may show its copy for a while). Markdown:
[](https://cve.bz/cve/CVE-2026-126193)
HTML:
<a href="https://cve.bz/cve/CVE-2026-126193"><img src="https://cve.bz/cve/badge/CVE-2026-126193.svg" alt="CVE-2026-126193"></a>
Affected
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| facelessuser soupsieve | >= 0.4, < 3.0 |
Fix and patched versions
soupsieve(PyPI): fixed in 3.0.2
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-7g44-g9rc-x53w | PyPI | soupsieve | >=0.4 <3.0.2 | 3.0.2 |
Linux distributions
| Distribution | Release | Package | Fixed in | Advisory |
|---|---|---|---|---|
| Ubuntu | 20.04:LTS, 22.04:LTS, 24.04:LTS and 2 more | soupsieve | no fix listed | UBUNTU-CVE-2026-126193 |
From the distributions' data via OSV.dev: Ubuntu Security Notices © Canonical Ltd., CC BY-SA 4.0. Modified: reformatted and linked to CVE records. Credits. On the distributions' own pages: Ubuntu.
Attack patterns (CAPEC)
- CAPEC-230 Serialized Data with Nested Payloads Likelihood: Medium · Severity: High
- CAPEC-231 Oversized Serialized Data Payloads Likelihood: Medium · Severity: High
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.