CVE-2024-6839: Flask cors Flask-CORS Improper Regex Path Matching Vulnerability

MODERATE
Advisory Identifier: GHSA-7rxf-gvfg-47g4
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CVSS 4.3
CWE-41
Published
Advisory Summary

CVE-2024-6839 is a MODERATE (CVSS 4.3) flask-cors improper regex path matching vulnerability (CWE-41: Improper Resolution of Path Equivalence) affecting Flask cors libraries in the PyPI ecosystem. The issue involves flask-cors improper regex path matching vulnerability. Remediation is available by upgrading affected packages to version 6.0.0.

CVE-2024-6839 at a Glance

CVE Identifier CVE-2024-6839
GHSA Identifier GHSA-7rxf-gvfg-47g4
Severity MODERATE
CVSS v3.1 Base Score 4.3
CWE Classification CWE-41: Improper Resolution of Path Equivalence
Affected Product Flask cors
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 4.3

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N).

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

How to Fix CVE-2024-6839

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

flask-cors fixed: 6.0.0 
pip install flask-cors>=6.0.0
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 flask-cors

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2024-6839, inspect your installed packages using pip:

pip show flask-cors

Analyze the terminal output to locate any version of Flask cors in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 6.0.0), your application is affected.

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

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-41: Improper Resolution of Path Equivalence, where the product is vulnerable to file system contents disclosure through path equivalence. path equivalence involves the use of special characters in file and directory names. the associated manipulations are intended to generate multiple names for the same object. In Flask cors, 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

corydolphin/flask-cors version 5.0.1 contains an improper regex path matching vulnerability. The plugin prioritizes longer regex patterns over more specific ones when matching paths, which can lead to less restrictive CORS policies being applied to sensitive endpoints. This mismatch in regex pattern priority allows unauthorized cross-origin access to sensitive data or functionality, potentially exposing confidential information and increasing the risk of unauthorized actions by malicious actors.

CVE-2024-6839 Affected Flask cors Versions

1 component(s)
Fixed Versions:
6.0.0
Product / Package Ecosystem Affected Versions Fixed Version
flask-cors
pypi/flask-cors
PyPI
< 6.0.0
6.0.0

References

NVD — CVE-2024-6839 NVD
https://nvd.nist.gov/vuln/detail/CVE-2024-6839
Security Fix Commit FIX COMMIT
https://github.com/corydolphin/flask-cors/commit/e970988bea563e05e8b8f53fa7bcc134b5bf5c5f
Flask cors Source Repository REPOSITORY
https://github.com/corydolphin/flask-cors
Flask cors Source Repository REPOSITORY
https://github.com/corydolphin/flask-cors/blob/4.0.1/flask_cors/core.py#L73
huntr.com/bounties/403eb1fc-8... WEB
https://huntr.com/bounties/403eb1fc-86f4-4820-8eba-0f3dfae9f2b4
lists.debian.org/debian-lts-announce... WEB
https://lists.debian.org/debian-lts-announce/2025/05/msg00049.html

Frequently Asked Questions

What is CVE-2024-6839?
CVE-2024-6839 is a security vulnerability in Flask cors involving Flask-CORS improper regex path matching vulnerability under CWE-41: Improper Resolution of Path Equivalence.
Which Flask cors versions are affected?
Affected versions include releases prior to 6.0.0 across affected packages: flask-cors.
What version fixes CVE-2024-6839?
Upgrading to 6.0.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is flask-cors affected?
Yes, flask-cors is affected in releases prior to 6.0.0. Upgrade your dependency to 6.0.0 or later.
What is the CVSS score of CVE-2024-6839?
CVE-2024-6839 has a CVSS v3.1 base score of 4.3 (MODERATE) with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N.
What CWE is associated with CVE-2024-6839?
CVE-2024-6839 is classified under CWE-41: Improper Resolution of Path Equivalence (The product is vulnerable to file system contents disclosure through path equivalence. Path equivalence involves the use of special characters in file and directory names. The associated manipulations are intended to generate multiple names for the same object.).
How can I check PyPI dependencies for CVE-2024-6839?
Run the dependency tree command: 'pip show flask-cors'. 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-7rxf-gvfg-47g4",
  "modified" : "2025-11-03T21:33:11Z",
  "published" : "2025-03-20T12:32:45Z",
  "aliases" : [ "CVE-2024-6839" ],
  "summary" : "Flask-CORS improper regex path matching vulnerability",
  "details" : "corydolphin/flask-cors version 5.0.1 contains an improper regex path matching vulnerability. The plugin prioritizes longer regex patterns over more specific ones when matching paths, which can lead to less restrictive CORS policies being applied to sensitive endpoints. This mismatch in regex pattern priority allows unauthorized cross-origin access to sensitive data or functionality, potentially exposing confidential information and increasing the risk of unauthorized actions by malicious actors.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "flask-cors"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "6.0.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 5.0.1"
    }
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2024-6839"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/corydolphin/flask-cors/commit/e970988bea563e05e8b8f53fa7bcc134b5bf5c5f"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/corydolphin/flask-cors"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/corydolphin/flask-cors/blob/4.0.1/flask_cors/core.py#L73"
  }, {
    "type" : "WEB",
    "url" : "https://huntr.com/bounties/403eb1fc-86f4-4820-8eba-0f3dfae9f2b4"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2025/05/msg00049.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-41" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-03-22T00:06:34Z",
    "nvd_published_at" : "2025-03-20T10:15:33Z"
  }
}