GHSA-7r87-cj48-wj45
Vulnerability from github
Published
2022-04-26 21:19
Modified
2024-09-20 21:03
Severity ?
5.3 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
6.9 (Medium) - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
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

Show details on source website

To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "flask-session-captcha"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.2.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2022-24880"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-253",
      "CWE-394",
      "CWE-754"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2022-04-26T21:19:52Z",
    "nvd_published_at": "2022-04-25T22:15:00Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\nflask-session-captcha is a package which allows users to extend Flask by adding an image based captcha stored in a server side session.\n\nThe `captcha.validate()` function would return `None` if passed no value (e.g. by submitting a request with an empty form).\n\nIf implementing users were checking the return value to be **False**, the captcha verification check could be bypassed.\n\nSample vulnerable code:\n```python\nif captcha.validate() == False:\n    ... # abort\nelse:\n   ... # do stuff\n```\n\n### Patches\nA new version (1.2.1) is available that fixes the issue.\n\n### Workarounds\nUsers can workaround the issue by not explicitly checking that the value is False. \n\nChecking the return value less explicitly should still work. \n\n```python\nif not captcha.validate():\n    ... # abort\nelse:\n   ... # do stuff\n```\n\n```python\nif captcha.validate():\n    ... # do stuff\nelse:\n   ... # abort\n```\n\n### References\nhttps://github.com/Tethik/flask-session-captcha/pull/27\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [the github repo](https://github.com/Tethik/flask-session-captcha)\n",
  "id": "GHSA-7r87-cj48-wj45",
  "modified": "2024-09-20T21:03:06Z",
  "published": "2022-04-26T21:19:52Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/Tethik/flask-session-captcha/security/advisories/GHSA-7r87-cj48-wj45"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-24880"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Tethik/flask-session-captcha/pull/27"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Tethik/flask-session-captcha/commit/2811ae23a38d33b620fb7a07de8837c6d65c13e4"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/Tethik/flask-session-captcha"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Tethik/flask-session-captcha/releases/tag/v1.2.1"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/flask-session-captcha/PYSEC-2022-193.yaml"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Potential Captcha Validate Bypass in flask-session-captcha"
}


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