GHSA-7r87-cj48-wj45 Potential Captcha Validate Bypass in flask-session-captcha

• PyPI flask-session-captcha: < 1.2.1 → fixed in 1.2.1

Impact flask-session-captcha is a package which allows users to extend Flask by adding an image based captcha stored in a server side session. The `captcha.validate()` function would return `None` if passed no value (e.g. by submitting a request with an empty form). If implementing users were checking the return value to be False, the captcha verification check could be bypassed. Sample vulnerable code: ```python if captcha.validate() == False: ... # abort else: ... # do stuff ``` Patches A new version (1.2.1) is available that fixes the issue. Workarounds Users can workaround the issue by not explicitly checking that the value is False. Checking the return value less explicitly should still work. ```python if not captcha.validate(): ... # abort else: ... # do stuff ``` ```python if captcha.validate(): ... # do stuff else: ... # abort ``` References https://github.com/Tethik/flask-session-captcha/pull/27 For more information If you have any questions or comments about this advisory: • Open an issue in the github repo