{"id":"CVE-2021-33571","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-33571","generatedAt":"2026-10-28T04:17:29.495Z","title":"This may allow a bypass of access control that is based on IP addresses.","description":"In Django 2.2 before 2.2.24, 3.x before 3.1.12, and 3.2 before 3.2.4, URLValidator, validate_ipv4_address, and validate_ipv46_address do not prohibit leading zero characters in octal literals. This may allow a bypass of access control that is based on IP addresses. (validate_ipv4_address and validate_ipv46_address are unaffected with Python 3.9.5+..) .","published":"2021-06-08T18:15:09.000Z","lastModified":"2026-06-17T03:54:49.000Z","status":"Modified","sourceIdentifier":"cve@mitre.org","cvss":{"version":"3.1","score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"},"cwe":["CWE-918"],"affected":["djangoproject/django","fedoraproject/fedora"],"epss":{"score":0.0526,"percentile":0.92506,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (5.26%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://docs.djangoproject.com/en/3.2/releases/security/","tags":["Patch","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://github.com/django/django/commit/203d4ab9ebcd72fc4d6eb7398e66ed9e474e118e","source":"cve@mitre.org"},{"url":"https://github.com/django/django/commit/9f75e2e562fa0c0482f3dde6fc7399a9070b4a3d","source":"cve@mitre.org"},{"url":"https://github.com/django/django/commit/f27c38ab5d90f68c9dd60cabef248a570c0be8fc","source":"cve@mitre.org"},{"url":"https://groups.google.com/g/django-announce/c/sPyjSKMi8Eo","tags":["Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/B4SQG2EAF4WCI2SLRL6XRDJ3RPK3ZRDV/","source":"cve@mitre.org"},{"url":"https://security.netapp.com/advisory/ntap-20210727-0004/","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://www.djangoproject.com/weblog/2021/jun/02/security-releases/","tags":["Patch","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://docs.djangoproject.com/en/3.2/releases/security/","tags":["Patch","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/django/django/commit/203d4ab9ebcd72fc4d6eb7398e66ed9e474e118e","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/django/django/commit/9f75e2e562fa0c0482f3dde6fc7399a9070b4a3d","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/django/django/commit/f27c38ab5d90f68c9dd60cabef248a570c0be8fc","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://groups.google.com/g/django-announce/c/sPyjSKMi8Eo","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/B4SQG2EAF4WCI2SLRL6XRDJ3RPK3ZRDV/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20210727-0004/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.djangoproject.com/weblog/2021/jun/02/security-releases/","tags":["Patch","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-33571","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}