CVE-2021-29921EPSS p93.9%

CVE-2021-29921CVE-2021-29921

python / python

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.

Scoring

CVSS 9.8 ()
VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS6.88% probability of exploitation · percentile 93.9% · 2026-10-10T12:00:23Z
Last modified2026-10-08
Sourced from NVD + FIRST.org EPSS. Curated for EU compliance use cases by Adam Lundqvist, Founder at SQUR.