CVE-2024-6866: Flask cors Flask-CORS Vulnerable To Improper Handling Vulnerability

MODERATE
Advisory Identifier: GHSA-43qf-4rqw-9q2g
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CVSS 5.3
CWE-178
Published
Advisory Summary

CVE-2024-6866 is a MODERATE (CVSS 5.3) flask-cors vulnerable to improper handling vulnerability (CWE-178: Improper Handling of Case Sensitivity) affecting Flask cors libraries in the PyPI ecosystem. The issue involves flask-cors vulnerable to improper handling of case sensitivity. Remediation is available by upgrading affected packages to version 6.0.0.

CVE-2024-6866 at a Glance

CVE Identifier CVE-2024-6866
GHSA Identifier GHSA-43qf-4rqw-9q2g
Severity MODERATE
CVSS v3.1 Base Score 5.3
CWE Classification CWE-178: Improper Handling of Case Sensitivity
Affected Product Flask cors
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 5.3

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

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

How to Fix CVE-2024-6866

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-2024-6866, 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-178: Improper Handling of Case Sensitivity, where the product does not properly account for differences in case sensitivity when accessing or determining the properties of a resource, leading to inconsistent results. 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 a vulnerability where the request path matching is case-insensitive due to the use of the `try_match` function, which is originally intended for matching hosts. This results in a mismatch because paths in URLs are case-sensitive, but the regex matching treats them as case-insensitive. This misconfiguration can lead to significant security vulnerabilities, allowing unauthorized origins to access paths meant to be restricted, resulting in data exposure and potential data leaks.

CVE-2024-6866 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-2024-6866 NVD
https://nvd.nist.gov/vuln/detail/CVE-2024-6866
Security Fix Commit FIX COMMIT
https://github.com/corydolphin/flask-cors/commit/eb39516a3c96b90d0ae5f51293972395ec3ef358
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/extension.py#L195
huntr.com/bounties/808c11af-f... WEB
https://huntr.com/bounties/808c11af-faee-43a8-824b-b5ab4f62b9e6
lists.debian.org/debian-lts-announce... WEB
https://lists.debian.org/debian-lts-announce/2025/05/msg00049.html

Frequently Asked Questions

What is CVE-2024-6866?
CVE-2024-6866 is a security vulnerability in Flask cors involving Flask-CORS vulnerable to Improper Handling of Case Sensitivity under CWE-178: Improper Handling of Case Sensitivity.
Which Flask cors versions are affected?
Affected versions include releases prior to 6.0.0 across affected packages: flask-cors.
What version fixes CVE-2024-6866?
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-2024-6866?
CVE-2024-6866 has a CVSS v3.1 base score of 5.3 (MODERATE) with vector string CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N.
What CWE is associated with CVE-2024-6866?
CVE-2024-6866 is classified under CWE-178: Improper Handling of Case Sensitivity (The product does not properly account for differences in case sensitivity when accessing or determining the properties of a resource, leading to inconsistent results.).
How can I check PyPI dependencies for CVE-2024-6866?
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-43qf-4rqw-9q2g",
  "modified" : "2025-11-03T21:33:12Z",
  "published" : "2025-03-20T12:32:45Z",
  "aliases" : [ "CVE-2024-6866" ],
  "summary" : "Flask-CORS vulnerable to Improper Handling of Case Sensitivity",
  "details" : "corydolphin/flask-cors version 5.0.1 contains a vulnerability where the request path matching is case-insensitive due to the use of the `try_match` function, which is originally intended for matching hosts. This results in a mismatch because paths in URLs are case-sensitive, but the regex matching treats them as case-insensitive. This misconfiguration can lead to significant security vulnerabilities, allowing unauthorized origins to access paths meant to be restricted, resulting in data exposure and potential data leaks.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/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-2024-6866"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/corydolphin/flask-cors/commit/eb39516a3c96b90d0ae5f51293972395ec3ef358"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/corydolphin/flask-cors"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/corydolphin/flask-cors/blob/4.0.1/flask_cors/extension.py#L195"
  }, {
    "type" : "WEB",
    "url" : "https://huntr.com/bounties/808c11af-faee-43a8-824b-b5ab4f62b9e6"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2025/05/msg00049.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-178" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-03-21T22:16:04Z",
    "nvd_published_at" : "2025-03-20T10:15:34Z"
  }
}