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CVE-2021-29921 Critical

CVE-2021-29921

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.

Exploit probability 6.9%
Published May 6, 2021
Required by Not available
Last source change August 7, 2026

02 / AFFECTED SOFTWARE

Affected packages

Unknown Unknown

4 explicit affected versions

Bitnami libpython
Bitnami python
Bitnami python-min
Unknown Unknown

285 explicit affected versions

03 / CONNECTIONS

Connected vulnerabilities

04 / EVIDENCE

Source records

Open Source Vulnerabilities BIT-python-2021-29921

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.

View original source
Open Source Vulnerabilities PSF-2021-2

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.

View original source
Open Source Vulnerabilities BIT-libpython-2021-29921

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.

View original source
Open Source Vulnerabilities BIT-python-min-2021-29921

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.

View original source
Open Source Vulnerabilities CVE-2021-29921

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.

View original source

05 / REFERENCES

Further evidence