ubuntu-cve-2021-23385
Vulnerability from osv_ubuntu
Published
2022-08-02 14:15
Modified
2025-07-16 04:57
Summary
Details

This affects all versions of package Flask-Security. When using the get_post_logout_redirect and get_post_login_redirect functions, it is possible to bypass URL validation and redirect a user to an arbitrary URL by providing multiple back slashes such as \\evil.com/path. This vulnerability is only exploitable if an alternative WSGI server other than Werkzeug is used, or the default behaviour of Werkzeug is modified using 'autocorrect_location_header=False. Note: Flask-Security is not maintained anymore.

Severity
6.1 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
5.4 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "python3-flask-security",
            "binary_version": "1.7.5-2ubuntu0.18.04.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "flask-security",
        "purl": "pkg:deb/ubuntu/flask-security@1.7.5-2ubuntu0.18.04.1~esm1?arch=source\u0026distro=esm-apps/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.7.5-2ubuntu0.18.04.1~esm1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.7.5-1",
        "1.7.5-2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "python3-flask-security",
            "binary_version": "1.7.5-2ubuntu0.20.04.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "flask-security",
        "purl": "pkg:deb/ubuntu/flask-security@1.7.5-2ubuntu0.20.04.1?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.7.5-2ubuntu0.20.04.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.7.5-2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "python3-flask-security",
            "binary_version": "4.0.0-1ubuntu0.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "flask-security",
        "purl": "pkg:deb/ubuntu/flask-security@4.0.0-1ubuntu0.1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.0.0-1ubuntu0.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.0.0-1"
      ]
    }
  ],
  "aliases": [],
  "details": "This affects all versions of package Flask-Security. When using the get_post_logout_redirect and get_post_login_redirect functions, it is possible to bypass URL validation and redirect a user to an arbitrary URL by providing multiple back slashes such as \\\\\\evil.com/path. This vulnerability is only exploitable if an alternative WSGI server other than Werkzeug is used, or the default behaviour of Werkzeug is modified using \u0027autocorrect_location_header=False. **Note:** Flask-Security is not maintained anymore.",
  "id": "UBUNTU-CVE-2021-23385",
  "modified": "2025-07-16T04:57:02Z",
  "published": "2022-08-02T14:15:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2021-23385"
    },
    {
      "type": "REPORT",
      "url": "https://security.snyk.io/vuln/SNYK-PYTHON-FLASKSECURITY-1293234"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/mattupstate/flask-security"
    },
    {
      "type": "REPORT",
      "url": "https://snyk.io/blog/url-confusion-vulnerabilities/"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-23385"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-6792-1"
    }
  ],
  "related": [
    "USN-6792-1"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2021-23385"
  ]
}



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Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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