CSRF Vuln can expose user's QRcode
Impact
When a user is setting up two-factor authentication using an authenticator app, a QRcode is generated and made available via a GET request to /tf-qrcode. Since GETs do not have any CSRF protection, it is possible a malicious 3rd party could access the QRcode and therefore gain access to two-factor authentication codes. Note that the /tf-qrcode endpoint is ONLY accessible while the user is initially setting up their device. Once setup is complete, there is no vulnerability.
Patches
This is fixed in the upcoming 4.0.0 release.
Workarounds
You can provide your own URL for fetching the QRcode by defining SECURITY_TWO_FACTOR_QRCODE_URL and providing your own implementation (that presumably required a POST with CSRF protection). This would require changing the two-factor setup template as well.
References
None.
For more information
If you have any questions or comments about this advisory:
- Read this pull request: #423
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | flask-security-too | >= 3.2.0, < 3.4.5 | 3.4.5 |
References
- Weakness (CWE)
CWE-352- Platform
- Python (PyPI)
- Package
flask-security-too- Disclosed
- 08.04.2021
- Updated
- 11.10.2026 12:18
Sources and licenses
OSV / GitHub Advisory Database - GHSA-fxq4-r6mr-9x64 - CC BY 4.0
Vulnerability history: flask-security-too
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 6
- First → latest
- 01.2021 07.2026
- Without a fix
- 1
- Exploited in attacks
- 0
Severity breakdown
- High 1
- Medium 3
- Low 2
Disclosures per year
- 2021: 3
- 2022: 0
- 2023: 1
- 2024: 0
- 2025: 0
- 2026: 2
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CSRF Vuln can expose user's QRcode this entry
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