Vulnerabilities in pkg:pypi/leo

PACKAGE
Advisory Identifier: GHSA-x38q-xg2h-rxgx
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Advisory Summary

CVE-2020-23478 is a HIGH (CVSS 7.5) denial of service vulnerability (CWE-1333: Inefficient Regular Expression Complexity) affecting Leo libraries in the PyPI ecosystem. The issue involves regular expression denial of service in leo editor. Remediation is available by upgrading affected packages to version 6.3.

1 Known Advisory Record(s)
Package Vulnerability Intelligence

pkg:pypi/leo

1 Known Advisory Record(s)

Vulnerability advisories affecting package pkg:pypi/leo. Select an advisory below to view technical details or fixes.

Advisory ID CVE / NVD Severity Summary
GHSA-x38q-xg2h-rxgx CVE-2020-23478 HIGH Regular Expression Denial of Service in Leo Editor

CVE-2020-23478 at a Glance

CVE Identifier CVE-2020-23478
GHSA Identifier GHSA-x38q-xg2h-rxgx
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-1333: Inefficient Regular Expression Complexity
Affected Product Leo
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-2020-23478

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

leo fixed: 6.3 
pip install leo>=6.3
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 leo

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2020-23478, inspect your installed packages using pip:

pip show leo

Analyze the terminal output to locate any version of Leo in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 6.3), your application is affected.

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

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-1333: Inefficient Regular Expression Complexity, where the product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential. In Leo, 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

Leo Editor v6.2.1 was discovered to contain a regular expression denial of service (ReDoS) vulnerability in the component plugins/importers/dart.py.

CVE-2020-23478 Affected Leo Versions

1 component(s)
Fixed Versions:
6.3
Product / Package Ecosystem Affected Versions Fixed Version
leo
pypi/leo
PyPI
< 6.3
6.3

References

NVD — CVE-2020-23478 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-23478
Leo Source Repository REPOSITORY
https://github.com/leo-editor/leo-editor/issues/1597
Security Fix Commit FIX COMMIT
https://github.com/leo-editor/leo-editor/commit/029833689060ee73f1bc1708cf4b182f0c66ec8e
GitHub Advisory / Wiki ADVISORY
https://github.com/advisories/GHSA-x38q-xg2h-rxgx
Leo Source Repository REPOSITORY
https://github.com/leo-editor/leo-editor
Leo Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/leo/PYSEC-2021-338.yaml

Frequently Asked Questions

What is CVE-2020-23478?
CVE-2020-23478 is a security vulnerability in Leo involving Regular Expression Denial of Service in Leo Editor under CWE-1333: Inefficient Regular Expression Complexity.
Which Leo versions are affected?
Affected versions include releases prior to 6.3 across affected packages: leo.
What version fixes CVE-2020-23478?
Upgrading to 6.3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is leo affected?
Yes, leo is affected in releases prior to 6.3. Upgrade your dependency to 6.3 or later.
What is the CVSS score of CVE-2020-23478?
CVE-2020-23478 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-2020-23478?
CVE-2020-23478 is classified under CWE-1333: Inefficient Regular Expression Complexity (The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.).
How can I check PyPI dependencies for CVE-2020-23478?
Run the dependency tree command: 'pip show leo'. 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-x38q-xg2h-rxgx",
  "modified" : "2024-09-27T21:45:23Z",
  "published" : "2021-09-23T23:14:28Z",
  "aliases" : [ "CVE-2020-23478" ],
  "summary" : "Regular Expression Denial of Service in Leo Editor",
  "details" : "Leo Editor v6.2.1 was discovered to contain a regular expression denial of service (ReDoS) vulnerability in the component plugins/importers/dart.py.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "leo"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "6.3"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 6.2.1"
    }
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-23478"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/leo-editor/leo-editor/issues/1597"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/leo-editor/leo-editor/commit/029833689060ee73f1bc1708cf4b182f0c66ec8e"
  }, {
    "type" : "ADVISORY",
    "url" : "https://github.com/advisories/GHSA-x38q-xg2h-rxgx"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/leo-editor/leo-editor"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/leo/PYSEC-2021-338.yaml"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1333", "CWE-697" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-09-23T16:37:27Z",
    "nvd_published_at" : "2021-09-22T20:15:00Z"
  }
}