A vulnerability in corydolphin/flask-cors version 4.0.1 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.

The remote Ubuntu 20.04 LTS / 22.04 LTS / 24.04 LTS / 24.10 / 25.04 host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-7612-1 advisory.

    It was discovered that Flask-CORS did not correctly handle certain regular expressions. A remote attacker     could possibly use this issue to leak sensitive information or bypass authentication mechanisms.
    (CVE-2024-6839) It was discovered that Flask-CORS allowed certain CORS headers to be enabled by default. A     remote attacker could possibly use this issue to leak sensitive information. This issue only affected     Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS and Ubuntu 24.10. (CVE-2024-6221)

    It was discovered that Flask-CORS did not correctly handle case sensitivity when matching paths. A remote     attacker could possibly use this issue to leak sensitive information. (CVE-2024-6866)

    It was discovered that Flask-CORS did not correctly handle certain characters in URL paths. A remote     attacker could possibly use this issue to leak sensitive information or bypass authentication mechanisms.
    (CVE-2024-6844)

    Elias Hohl was discovered that Flask-CORS did not correctly sanitize log entries. A remote attacker could     possibly use this issue to corrupt log files. This issue only affected Ubuntu 20.04 LTS, Ubuntu 22.04 LTS     and Ubuntu 24.04 LTS. (CVE-2024-1681)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Debian 11 host has a package installed that is affected by multiple vulnerabilities as referenced in the dla-4197 advisory.

    -------------------------------------------------------------------------     Debian LTS Advisory DLA-4197-1                debian-lts@lists.debian.org     https://www.debian.org/lts/security/                       Daniel Leidert     May 31, 2025                                  https://wiki.debian.org/LTS
    -------------------------------------------------------------------------

    Package        : python-flask-cors     Version        : 3.0.9-2+deb11u1     CVE ID         : CVE-2024-1681 CVE-2024-6839 CVE-2024-6844 CVE-2024-6866     Debian Bug     : 1069764 1100988

    Multiple security issues were discovered in Flask-CORS, a Flask     extension for handling Cross Origin Resource Sharing (CORS).

    CVE-2024-1681

       Due to a log injection vulnerability when the log level is set to        debug, an attacker can inject fake log entries into the log file by        sending a specially crafted GET request containing a CRLF sequence        in the request path.

    CVE-2024-6839

       An improper regex path matching vulnerability due to prioritizing        longer regex patterns over more specific ones when matching paths,        can lead to less restrictive CORS policies being applied to        sensitive endpoints.

    CVE-2024-6844

       An inconsistent CORS matching due to the handling of the '+'        character in URL paths leads to incorrect path normalization,        causing potential mismatches in CORS configuration.

    CVE-2024-6866

       The request path matching is case-insensitive. This results in a        mismatch because paths in URLs are case-sensitive. This        misconfiguration can lead to significant security vulnerabilities,        allowing unauthorized origins to access paths meant to be        restricted.

    For Debian 11 bullseye, these problems have been fixed in version     3.0.9-2+deb11u1.

    We recommend that you upgrade your python-flask-cors packages.

    For the detailed security status of python-flask-cors please refer to     its security tracker page at:
    https://security-tracker.debian.org/tracker/python-flask-cors

    Further information about Debian LTS security advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://wiki.debian.org/LTS     Attachment:
    signature.asc     Description: This is a digitally signed message part

Tenable has extracted the preceding description block directly from the Debian security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - A vulnerability in corydolphin/flask-cors version 4.0.1 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)

ID	Name	Product	Family	Severity
241350	Ubuntu 20.04 LTS / 22.04 LTS / 24.04 LTS / 24.10 / 25.04 : Flask-CORS vulnerabilities (USN-7612-1)	Nessus	Ubuntu Local Security Checks	high
237621	Debian dla-4197 : python3-flask-cors - security update	Nessus	Debian Local Security Checks	medium
427720	SCA: security update for flask-cors (GHSA-8vgw-p6qm-5gr7)	Tenable Cloud Security	SCA Checks	medium
427720	SCA: security update for flask-cors (GHSA-8vgw-p6qm-5gr7)	Tenable Self-Hosted Container Security	SCA Checks	medium

Detections

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CVE-2024-6844

medium

Tenable Plugins

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medium

medium

medium