CSRF in Flask-Middleware Flask-Security-Too
CVE-2021-21241
The Python "Flask-Security-Too" package is used for adding security features to your Flask application. It is an is a independently maintained version of Flask-Security based on the 3.0.0 version of Flask-Security. In Flask-Security-Too from version 3.3.0 and before version 3.4.5, the /login and /change endpoints can return the authenticated user's authentication token in response to a GET request. Since GET requests aren't protected with a CSRF token, this could lead to a malicious 3rd party site acquiring the authentication token. Version 3.4.5 and version 4.0.0 are patched. As a workaround, if you aren't using authentication tokens - you can set the SECURITY_TOKEN_MAX_AGE to "0" (seconds) which should make the token unusable.
Vulnerability class: CSRF (Cross-Site Request Forgery)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.4 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.009 (58.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 59th percentile — 58.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: 0.000
Affected products
- Flask-Middleware Flask-Security-Too — versions >= 3.3.0, < 3.4.5
- Flask-Security-Too Project
Weakness classification (CWE)
References
- github.com/Flask-Middleware/flask-security/security/advisories/GHSA-hh7m-rx4f-4… (Third Party Advisory)
- github.com/Flask-Middleware/flask-security/pull/422 (Patch, Third Party Advisory)
- github.com/Flask-Middleware/flask-security/commit/61d313150b5f620d0b800896c4f21… (Patch, Third Party Advisory)
- github.com/Flask-Middleware/flask-security/commit/6d50ee9169acf813257c37b75babe… (Patch, Third Party Advisory)
- github.com/Flask-Middleware/flask-security/releases/tag/3.4.5 (Third Party Advisory)
- pypi.org/project/Flask-Security-Too (Product, Third Party Advisory)
Frequently asked questions
- What is CVE-2021-21241?
- CVE-2021-21241 is a high-severity vulnerability in Flask-Middleware Flask-Security-Too, classified under Cross-Site Request Forgery (CSRF). CVSS score: 7.4/10. Published 2021-01-11.
- How severe is CVE-2021-21241?
- High severity. CVSS v3 base score is 7.4 out of 10.