CVE-2026-40199: medium-severity vulnerability in STIGTSP Net::CIDR::Lite
Net::CIDR::Lite versions before 0.23 for Perl mishandles IPv4 mapped IPv6 addresses, which may allow IP ACL bypass
Published · Updated
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 6.5epss 0.3%
Net::CIDR::Lite versions before 0.23 for Perl mishandles IPv4 mapped IPv6 addresses, which may allow IP ACL bypass.
_pack_ipv6() includes the sentinel byte from _pack_ipv4() when building the packed representation of IPv4 mapped addresses like ::ffff:192.168.1.1. This produces an 18 byte value instead of 17 bytes, misaligning the IPv4 part of the address.
The wrong length causes incorrect results in mask operations (bitwise AND truncates to the shorter operand) and in find() / bin_find() which use Perl string comparison (lt/gt). This can cause find() to incorrectly match or miss addresses.
Example:
my $cidr = Net::CIDR::Lite->new("::ffff:192.168.1.0/120");
$cidr->find("::ffff:192.168.2.0"); # incorrectly returns true
This is triggered by valid RFC 4291 IPv4 mapped addresses (::ffff:x.x.x.x).
See also CVE-2026-40198, a related issue in the same function affecting malformed IPv6 addresses.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Affected products
STIGTSP · Net::CIDR::LiteRelated CVEs — STIGTSP Net::CIDR::Lite
In the same product, most dangerous first.
CVE-2026-40198HIGHNet::CIDR::Lite versions before 0.23 for Perl does not validate IPv6 group count, which may allow IP ACL bypassEPSS 0.3%CVE-2026-45190MEDIUMNet::CIDR::Lite versions before 0.24 for Perl does not properly validate IP address and CIDR mask inputs, which may allow IP ACL bypassEPSS 0.3%CVE-2026-45191MEDIUMNet::CIDR::Lite versions before 0.24 for Perl does not properly consider extraneous zero characters in CIDR mask values, which may allow IP ACL bypassEPSS 0.3%