# CVE-2020-35139: PYSEC-2026-1876 - FaucetSDN Ryu Denial of Service Vulnerability

Source: https://junglewise.ai/threats/cve-2020-35139-faucetsdn-ryu-denial-of-service-vulnerability  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-07  
License: CC BY 4.0 with a link back

CVE-2020-35139 · Severity: low · CVSS 3.1 · Published 2026-07-07

FaucetSDN Ryu Denial of Service Vulnerability

Technologies: [ryu (PyPI)](https://junglewise.ai/threats/technologies/ryu). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2020-35139 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2020-35139 being exploited in the wild.

**How severe is CVE-2020-35139?** Low severity, with a CVSS score of 3.1, published 7 July 2026.

**Which products and versions are affected?** ryu (PyPI) ECOSYSTEM:introduced=0,last_affected=4.34.

**Is there a fix for CVE-2020-35139?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**Am I affected by CVE-2020-35139?** Check whether you run ryu (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- ryu (PyPI) ECOSYSTEM:introduced=0,last_affected=4.34

## Identifiers

- CVE-2020-35139
- GHSA-4987-5p3p-9r27
- PYSEC-2026-1876

## Related threats

- [PYSEC-2026-1877 - Ryu Infinite Loop vulnerability](https://junglewise.ai/threats/cve-2024-34489-ryu-infinite-loop-vulnerability)
- [PYSEC-2026-1883 - Ryu Infinite Loop vulnerability](https://junglewise.ai/threats/cve-2024-34487-ryu-infinite-loop-vulnerability)
- [PYSEC-2026-1880 - Ryu Infinite Loop vulnerability](https://junglewise.ai/threats/cve-2024-34484-ryu-infinite-loop-vulnerability)
- [PYSEC-2026-1882 - Ryu Infinite Loop vulnerability](https://junglewise.ai/threats/cve-2024-34486-ryu-infinite-loop-vulnerability)
- [PYSEC-2026-1879 - Ryu Infinite Loop vulnerability](https://junglewise.ai/threats/cve-2024-34483-ryu-infinite-loop-vulnerability)