Security News > 2021 > May > Python also impacted by critical IP address validation vulnerability

The Python standard library ipaddress also suffers from the critical IP address validation vulnerability identical to the flaw that was reported in the "Netmask" library earlier this year.

The researchers who had discovered the critical flaw in netmask, also discovered the same flaw in this Python module and have procured a vulnerability identifier: CVE-2021-29921.

The regression bug crept into Python 3.x's ipaddress module as a result of a change made in 2019 by Python maintainers.

Of particular note is the fact, 127.0.0.1 is not a public IP address but a loopback address its ambiguous representation changes it to a public IP address leading to a different host altogether.

"Improper input validation of octal strings in Python 3.8.0 thru v3.10 stdlib ipaddress allows unauthenticated remote attackers to perform indeterminate on many programs that rely on Python stdlib ipaddress," state the researchers.

Although ipaddress module was introduced in Python 3.3, this regression bug crept into the module starting with Python version 3.8.0 through 3.10, according to the researchers.

News URL

https://www.bleepingcomputer.com/news/security/python-also-impacted-by-critical-ip-address-validation-vulnerability/