CVE-2026-40198

NameCVE-2026-40198
DescriptionNet::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.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
libnet-cidr-lite-perl (PTS)bullseye0.22-1vulnerable
forky, bookworm, trixie0.22-2vulnerable
sid0.22-3fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
libnet-cidr-lite-perlsource(unstable)0.22-3

Notes

[trixie] - libnet-cidr-lite-perl <no-dsa> (Minor issue, will be fixed via point release)
[bookworm] - libnet-cidr-lite-perl <no-dsa> (Minor issue, will be fixed via point release)
https://lists.security.metacpan.org/cve-announce/msg/38785616/
Fixed by: https://github.com/stigtsp/Net-CIDR-Lite/commit/25d65f85dbe4885959a10471725ec9d250a589c3 (0.23)
Tests: https://github.com/stigtsp/Net-CIDR-Lite/commit/380562e04f66026ba3859f76b3c8ae0489cbc750 (0.23)

Search for package or bug name: Reporting problems