GHSA-7r87-cj48-wj45

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GHSA-7r87-cj48-wj45

Summary: Potential Captcha Validate Bypass in flask-session-captcha

Details: ### 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](https://github.com/Tethik/flask-session-captcha)

References: https://github.com/Tethik/flask-session-captcha/security/advisories/GHSA-7r87-cj48-wj45, https://nvd.nist.gov/vuln/detail/CVE-2022-24880, https://github.com/Tethik/flask-session-captcha/pull/27, https://github.com/Tethik/flask-session-captcha/commit/2811ae23a38d33b620fb7a07de8837c6d65c13e4, https://github.com/Tethik/flask-session-captcha, https://github.com/Tethik/flask-session-captcha/releases/tag/v1.2.1, https://github.com/pypa/advisory-database/tree/main/vulns/flask-session-captcha/PYSEC-2022-193.yaml