# CVE-2022-24880: Potential Captcha Validate Bypass in flask-session-captcha

> Attackers can bypass captcha validation in flask-session-captcha by submitting empty forms, allowing automated abuse of protected endpoints.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Apr 2022
- **Updated:** 23 Apr 2025
- **Also known as:** GHSA-7r87-cj48-wj45, PYSEC-2022-193

## What is CVE-2022-24880?

CVE-2022-24880 is a medium-severity vulnerability in Tethik flask-session-captcha, published on 25 Apr 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-754 (Improper Check for Unusual or Exceptional Conditions), CWE-394 (Unexpected Status Code or Return Value), CWE-253 (Incorrect Check of Function Return Value)

## Which versions are affected by CVE-2022-24880?

3 open source packages ship an affected version, including flask-session-captcha. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `flask-session-captcha` | PyPI | All versions | 1.2.1 |
| `flask-session-captcha` | PyPI | All versions | 1.2.1 |
| `flask-session-captcha` | PyPI | All versions | 1.2.1 |

Products: Flask-Session-Captcha Project Flask-Session-Captcha.

## How do I fix CVE-2022-24880?

Upgrade flask-session-captcha to 1.2.1 or later.

## Is CVE-2022-24880 being exploited?

There is no known exploitation of CVE-2022-24880 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-24880 and fix it if it is affected.

What it is: CVE-2022-24880 is a medium-severity vulnerability in Tethik flask-session-captcha, published on 25 Apr 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2022-24880 in the wild and no public exploit code.

Affected packages and fixed versions:
- flask-session-captcha (PyPI): affected all versions; fixed in 1.2.1
- flask-session-captcha (PyPI): affected all versions; fixed in 1.2.1
- flask-session-captcha (PyPI): affected all versions; fixed in 1.2.1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2022-24880/ (Markdown: https://insights.sbomify.com/CVE-2022-24880/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-24880
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-24880
- OSV: https://osv.dev/vulnerability/CVE-2022-24880

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From sbomify Insights: https://insights.sbomify.com/CVE-2022-24880/
Summaries are generated and may contain mistakes; the official description above is the record.