ZeroDay Findings
Sign inSign up

Findings

CVE-2026-40198

Net::CIDR::Lite versions before 0.23 for Perl does not validate IPv6 group count, which may allow IP ACL bypass.

Published Apr 10, 2026 · updated Jun 17, 2026 · stigtsp net

Net::CIDR::Lite versions before 0.23 for Perl does not validate IPv6 group count, which may allow IP ACL bypass. _pack_ipv6() does not check that uncompressed IPv6 addresses (without ::) have exactly 8 hex groups. Inputs like "abcd", "1:2:3", or "1:2:3:4:5:6:7" are accepted and produce packed values of wrong length (3, 7, or 15 bytes instead of 17). The packed values are used internally for mask and comparison operations. find() and bin_find() use Perl string comparison (lt/gt) on these values, and comparing strings of different lengths gives wrong results. This can cause find() to incorrectly report an address as inside or outside a range. Example: my $cidr = Net::CIDR::Lite->new("::/8"); $cidr->find("1:2:3"); # invalid input, incorrectly returns true This is the same class of input validation issue as CVE-2021-47154 (IPv4 leading zeros) previously fixed in this module. See also CVE-2026-40199, a related issue in the same function affecting IPv4 mapped IPv6 addresses.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 10, 2026 · NIST NVD

    Detected

    Net::CIDR::Lite versions before 0.23 for Perl does not validate IPv6 group count, which may allow IP ACL bypass. _pack_ipv6() does not check that uncompressed IPv6 addresses (without ::) have exactly 8 hex groups. Inputs like "abcd", "1:2:3", or "1:2:3:4:5:6:7" are accepted and produce packed values of wrong length (3, 7, or 15 bytes instead of 17). The packed values are used internally for mask a

  2. Jun 17, 2026 · NIST NVD

    Updated

    Net::CIDR::Lite versions before 0.23 for Perl does not validate IPv6 group count, which may allow IP ACL bypass. _pack_ipv6() does not check that uncompressed IPv6 addresses (without ::) have exactly 8 hex groups. Inputs like "abcd", "1:2:3", or "1:2:3:4:5:6:7" are accepted and produce packed values of wrong length (3, 7, or 15 bytes instead of 17). The packed values are used internally for mask a

Affected

  • cpe stigtsp/net\

Sources

  • CVE.orgVulnerability recordCVE-2026-40198

    Official CVE identifier

    cve.org
  • NIST NVDVulnerability recordCVE-2026-40198

    Net::CIDR::Lite versions before 0.23 for Perl does not validate IPv6 group count, which may allow IP ACL bypass. _pack_ipv6() does not check that uncompressed IPv6 addresses (without ::) have exactly 8 hex groups. Inputs like "abcd", "1:2:3", or "1:2:3:4:5:6:7" are accepted and

    nvd.nist.gov

References