Net::CIDR::Set versions 0.10 through 0.13 for Perl does not properly handle leading zero characters in IP CIDR address strings, which could allow attackers to bypass access control that is based on IP addresses. Leading zeros are used to indicate octal numbers, which can confuse users who are intentionally using octal notation, as well as users who believe they are using decimal notation. Net::CIDR::Set used code from Net::CIDR::Lite, which had a similar vulnerability CVE-2021-47154.

• https://metacpan.org/release/RRWO/Net-CIDR-Set-0.14/changes
• https://github.com/robrwo/perl-Net-CIDR-Set/commit/be7d91e8446ad8013b08b4be313d666dab003a8a.patch
• https://blog.urth.org/2021/03/29/security-issues-in-perl-ip-address-distros/

Net::CIDR::Set versions through 0.20 for Perl accept non-ASCII IP addresses and netmasks. Unicode digits such as the Arabic-Indic One (U+0661) were accepted but not properly parsed as numbers. This could allow network masks to accept larger networks.

• https://metacpan.org/release/RRWO/Net-CIDR-Set-0.21/changes
• https://nvd.nist.gov/vuln/detail/CVE-2025-40911

Net::CIDR::Set versions through 0.20 for Perl did not validate IP addresses. The add method called the _encode method to parse addresses. If the addresses did not look like netmasks or network ranges, then they were assumed to single IP addresses and passed back to itself as a 32-bit or 128-bit netmask. If the argument was not a well-formed IP address, then this would lead to indefinite recursion. An attacker could use this to cause a denial of service.

• https://metacpan.org/release/RRWO/Net-CIDR-Set-0.21/changes

Net::CIDR::Set versions through 0.20 for Perl did not validate network masks. The mask portion of a network mask could contain Unicode digits such as the Arabic-Indic One (U+0661), or non-digits, which were ignored. This could allow network masks to accept larger networks. Leading zeros were also accepted, but treated as decimal instead of octal. This could lead to confusion about what networks are acceptable.

• https://metacpan.org/release/RRWO/Net-CIDR-Set-0.21/changes
• https://nvd.nist.gov/vuln/detail/CVE-2025-40911
• https://nvd.nist.gov/vuln/detail/CVE-2026-45191