CVE Catalog

CVE-2021-29921

CriticalCVSS 9.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Very high risk
6.88%

94th percentile - higher than 94% of all known CVEs

Summary

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.

Risk Assessment

IP-based access control mechanisms may be bypassed, enabling unauthorized access to protected resources.

Recommendation

Upgrade Python to version 3.9.5 or later. Do not rely solely on the ipaddress library for IP validation in access control mechanisms.

Other vulnerabilities in Python

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Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS