{"cve":"CVE-2021-29921","nvd":{"published":"2021-05-06T13:15:12.573","modified":"2026-10-08T22:17:09.223","status":"Modified","description":"In Python before 3,9,5, the ipaddress library mishandles leading zero characters in the octets of an IP address string. This (in some situations) allows attackers to bypass access control that is based on IP addresses.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":[],"references":["https://bugs.python.org/issue36384","https://docs.python.org/3/library/ipaddress.html","https://github.com/python/cpython/blob/63298930fb531ba2bb4f23bc3b915dbf1e17e9e1/Misc/NEWS.d/3.8.0a4.rst","https://github.com/python/cpython/pull/12577","https://github.com/python/cpython/pull/25099"],"products":["oracle:communications_cloud_native_core_automated_test_suite","oracle:communications_cloud_native_core_binding_support_function","oracle:communications_cloud_native_core_network_slice_selection_function","oracle:graalvm","oracle:zfs_storage_appliance_kit","python:python"],"source":"nvd","synced_at":"2026-10-19T21:18:09.669877188+00:00"},"epss":{"cve":"CVE-2021-29921","score":0.06882,"percentile":0.9402,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}