Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| corydolphin | corydolphin/flask-cors | unspecified – ≤ latest | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | python-flask-cors | 6.0.0-1 | — |
| Debian 13 | python-flask-cors | 6.0.0-1 | — |
| Debian 12 | python-flask-cors | 3.0.10-2+deb12u1 | — |
| Debian 11 | python-flask-cors | 3.0.9-2+deb11u1 | DLA-4197-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 22.04 LTS | python-flask-cors | 3.0.9-2ubuntu0.1 | USN-7612-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 24.04 LTS | python-flask-cors | 4.0.0-1ubuntu0.1~esm1 | USN-7612-1 |
| Ubuntu Pro 20.04 LTS | python-flask-cors | 3.0.8-2ubuntu0.1+esm1 | USN-7612-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | python-Flask-Cors | 6.0.2-1.1 | openSUSE-SU-2026:10485-1 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | kubeflow-jupyter-web-app | 1.10.0-r3 | — |
| Wolfi rolling | kubeflow-volumes-web-app | 1.10.0-r2 | — |
| Wolfi rolling | superset-6.0 | 6.0.0-r2 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | flask-cors | < 6.0.0 | 6.0.0 | GHSA-8vgw-p6qm-5gr7 |
Advisories 3
- USN-7612-1 python-flask-cors vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- openSUSE-SU-2026:10485-1 python311-Flask-Cors-6.0.2-1.1 on GA media SUSE / openSUSE Security Updates · Apr 4, 2026
- DLA-4197-1 python-flask-cors - security update Debian Security (DSA / DLA) · Mar 9, 2026