CVE-2022-24880
Potential Captcha Validate Bypass in flask-session-captcha
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
Description
flask-session-captcha is a package which allows users to extend Flask by adding an image based captcha stored in a server side session. In versions prior to 1.2.1, he `captcha.validate()` function would return `None` if passed no value (e.g. by submitting an having an empty form). If implementing users were checking the return value to be **False**, the captcha verification check could be bypassed. Version 1.2.1 fixes the issue. Users can workaround the issue by not explicitly checking that the value is False. Checking the return value less explicitly should still work.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Medium5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
| NVDNVD · Modified | 3.1 | Medium5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
- EPSS (exploitation in 30 days)
- 1.2% · top 32% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.3.
Weakness
- CWE-253: Incorrect Check of Function Return Value (opens in a new tab)All about CWE-253 and its CVEs
- CWE-394: Unexpected Status Code or Return Value (opens in a new tab)All about CWE-394 and its CVEs
- CWE-754: Improper Check for Unusual or Exceptional Conditions (opens in a new tab)All about CWE-754 and its CVEs
Affected products
Tethik · flask-session-captcha
- affected < 1.2.1
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- PyPIflask-session-captchaGHSA-7r87-cj48-wj45 (opens in a new tab)
References (4)
- https://github.com/Tethik/flask-session-captcha/security/advisories/GHSA-7r87-cj48-wj45 (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://github.com/Tethik/flask-session-captcha/pull/27 (opens in a new tab)x_refsource_MISCx_transferred
- https://github.com/Tethik/flask-session-captcha/commit/2811ae23a38d33b620fb7a07de8837c6d65c13e4 (opens in a new tab)x_refsource_MISCx_transferred
- https://github.com/Tethik/flask-session-captcha/releases/tag/v1.2.1 (opens in a new tab)x_refsource_MISCx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-7r87-cj48-wj45 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2022-24880)Record last updated .