CVE-2024-6844: Flask cors Flask-CORS Allows For Inconsistent CORS Vulnerability

MODERATE
Advisory Identifier: GHSA-8vgw-p6qm-5gr7
Share
CVSS 5.3
CWE-346
Published
Advisory Summary

CVE-2024-6844 is a MODERATE (CVSS 5.3) flask-cors allows for inconsistent cors vulnerability (CWE-346: Origin Validation Error) affecting Flask cors libraries in the PyPI ecosystem. The issue involves flask-cors allows for inconsistent cors matching. Remediation is available by upgrading affected packages to version 6.0.0.

CVE-2024-6844 at a Glance

CVE Identifier CVE-2024-6844
GHSA Identifier GHSA-8vgw-p6qm-5gr7
Severity MODERATE
CVSS v3.1 Base Score 5.3
CWE Classification CWE-346: Origin Validation Error
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:L/PR:N/UI:N/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 None (UI:N)
Scope Unchanged (S:U)
Confidentiality Low (C:L)
Integrity None (I:N)
Availability None (A:N)

How to Fix CVE-2024-6844

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-2024-6844, 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-346: Origin Validation Error, where the product does not properly verify that the source of data or communication is valid. 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

A vulnerability in corydolphin/flask-cors version 5.0.1 allows for inconsistent CORS matching due to the handling of the '+' character in URL paths. The request.path is passed through the unquote_plus function, which converts the '+' character to a space ' '. This behavior leads to incorrect path normalization, causing potential mismatches in CORS configuration. As a result, endpoints may not be matched correctly to their CORS settings, leading to unexpected CORS policy application. This can cause unauthorized cross-origin access or block valid requests, creating security vulnerabilities and usability issues.

CVE-2024-6844 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-2024-6844 NVD
https://nvd.nist.gov/vuln/detail/CVE-2024-6844
Security Fix Commit FIX COMMIT
https://github.com/corydolphin/flask-cors/commit/35d875319621bd129a38b2b823abf4a2f6cda536
Flask cors Source Repository REPOSITORY
https://github.com/corydolphin/flask-cors
Flask cors Source Repository REPOSITORY
https://github.com/corydolphin/flask-cors/blob/main/flask_cors/extension.py#L193
huntr.com/bounties/731a6cd4-d... WEB
https://huntr.com/bounties/731a6cd4-d05f-4fe6-8f5b-fe088d7b34e0
lists.debian.org/debian-lts-announce... WEB
https://lists.debian.org/debian-lts-announce/2025/05/msg00049.html

Frequently Asked Questions

What is CVE-2024-6844?
CVE-2024-6844 is a security vulnerability in Flask cors involving Flask-CORS allows for inconsistent CORS matching under CWE-346: Origin Validation Error.
Which Flask cors versions are affected?
Affected versions include releases prior to 6.0.0 across affected packages: flask-cors.
What version fixes CVE-2024-6844?
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-2024-6844?
CVE-2024-6844 has a CVSS v3.1 base score of 5.3 (MODERATE) with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.
What CWE is associated with CVE-2024-6844?
CVE-2024-6844 is classified under CWE-346: Origin Validation Error (The product does not properly verify that the source of data or communication is valid.).
How can I check PyPI dependencies for CVE-2024-6844?
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-8vgw-p6qm-5gr7",
  "modified" : "2025-11-03T21:33:12Z",
  "published" : "2025-03-20T12:32:45Z",
  "aliases" : [ "CVE-2024-6844" ],
  "summary" : "Flask-CORS allows for inconsistent CORS matching",
  "details" : "A vulnerability in corydolphin/flask-cors version 5.0.1 allows for inconsistent CORS matching due to the handling of the '+' character in URL paths. The request.path is passed through the unquote_plus function, which converts the '+' character to a space ' '. This behavior leads to incorrect path normalization, causing potential mismatches in CORS configuration. As a result, endpoints may not be matched correctly to their CORS settings, leading to unexpected CORS policy application. This can cause unauthorized cross-origin access or block valid requests, creating security vulnerabilities and usability issues.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/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-2024-6844"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/corydolphin/flask-cors/commit/35d875319621bd129a38b2b823abf4a2f6cda536"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/corydolphin/flask-cors"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/corydolphin/flask-cors/blob/main/flask_cors/extension.py#L193"
  }, {
    "type" : "WEB",
    "url" : "https://huntr.com/bounties/731a6cd4-d05f-4fe6-8f5b-fe088d7b34e0"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2025/05/msg00049.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-346" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-03-21T22:10:24Z",
    "nvd_published_at" : "2025-03-20T10:15:34Z"
  }
}