CVE-2020-35141: Ryu Denial of Service Vulnerability

HIGH
Advisory Identifier: GHSA-5x64-925v-h4gv
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CVSS 7.5
CWE-835 CWE-770
Published
Advisory Summary

CVE-2020-35141 is a HIGH (CVSS 7.5) denial of service vulnerability (CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')) affecting Ryu libraries in the PyPI ecosystem. The issue involves faucetsdn ryu denial of service vulnerability. Remediation is available in the latest vendor maintenance releases.

CVE-2020-35141 at a Glance

CVE Identifier CVE-2020-35141
GHSA Identifier GHSA-5x64-925v-h4gv
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')
Affected Product Ryu
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2020-35141

To remediate this vulnerability, upgrade all affected Ryu dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

ryu fixed: Latest secure release 
pip install ryu>=Latest secure release
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show ryu

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2020-35141, inspect your installed packages using pip:

pip show ryu

Analyze the terminal output to locate any version of Ryu in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The pip show ryu command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop'), where the product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop. In Ryu, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

An issue was discovered in `OFPQueueGetConfigReply` in `parser.py` in FaucetSDN Ryu version 4.34, allows remote attackers to cause a denial of service (DoS) (infinite loop).

CVE-2020-35141 Affected Ryu Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
ryu
pypi/ryu
PyPI
≤ 4.34

References

NVD — CVE-2020-35141 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-35141
Ryu Source Repository REPOSITORY
https://github.com/faucetsdn/ryu/issues/118
Ryu Source Repository REPOSITORY
https://github.com/faucetsdn/ryu

Frequently Asked Questions

What is CVE-2020-35141?
CVE-2020-35141 is a security vulnerability in Ryu involving FaucetSDN Ryu Denial of Service Vulnerability under CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop').
Which Ryu versions are affected?
Affected versions include releases prior to current release patches across affected packages: ryu.
What version fixes CVE-2020-35141?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is ryu affected?
Yes, ryu is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2020-35141?
CVE-2020-35141 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2020-35141?
CVE-2020-35141 is classified under CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop') (The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.).
How can I check PyPI dependencies for CVE-2020-35141?
Run the dependency tree command: 'pip show ryu'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-5x64-925v-h4gv",
  "modified" : "2023-08-18T15:48:16Z",
  "published" : "2023-08-11T15:30:46Z",
  "aliases" : [ "CVE-2020-35141" ],
  "summary" : "FaucetSDN Ryu Denial of Service Vulnerability",
  "details" : "An issue was discovered in `OFPQueueGetConfigReply` in `parser.py` in FaucetSDN Ryu version 4.34, allows remote attackers to cause a denial of service (DoS) (infinite loop).",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "ryu"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "4.34"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-35141"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/faucetsdn/ryu/issues/118"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/faucetsdn/ryu"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-770", "CWE-835" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-08-11T22:03:46Z",
    "nvd_published_at" : "2023-08-11T14:15:11Z"
  }
}