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Fencer Vulns
medium 5.3

CVE-2024-6844 json

Inconsistent CORS Matching Due to Handling of '+' in URL Path in corydolphin/flask-cors

published 2025-03-20 19 mo ago modified 2026-09-10 1 mo ago also GHSA-8vgw-p6qm-5gr7 , PYSEC-2026-1385 , EUVD-2025-6972

cvss
5.3
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 25%
public exploits
0
none known

Summary

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.

Patch / fix

  • pypi flask-cors 6.0.0
  • python-flask-cors Debian 12 3.0.10-2+deb12u1
  • python-flask-cors Debian 14, Debian 13 6.0.0-1

debian advisories DEBIAN-CVE-2024-6844

  • python-flask-cors Ubuntu 22.04 LTS 3.0.9-2ubuntu0.1
  • python-flask-cors Ubuntu Pro 20.04 LTS 3.0.8-2ubuntu0.1+esm1
  • python-flask-cors Ubuntu Pro 24.04 LTS 4.0.0-1ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2024-6844

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • python-Flask-Cors openSUSE Tumbleweed 6.0.2-1.1

opensuse advisories openSUSE-SU-2026:10485-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2024-6844 updated cvss 5.3

flask-cors: Inconsistent CORS Matching Due to Handling of '+' in URL Path in corydolphin/flask-cors

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
19 mo ago

Exploit prediction

0.32% chance of exploitation in the next 30 days, higher than 25% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • huntr.com https://huntr.com/bounties/731a6cd4-d05f-4fe6-8f5b-fe088d7b34e0 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.0 5.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
GitHub 3.0 5.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
OSV 3.0 5.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Affected packages

ecosystem package affected fixed in
pypi flask-cors
<6.0.0
6.0.0

Affected products

  • corydolphin corydolphin/flask-cors

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.