Net::CIDR::Lite versions before 0.23 for Perl mishandles IPv4 mapped IPv6 addresses, which may allow IP ACL bypass

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Summary

CVECVE-2026-40199
StatePUBLISHED
AssignerCPANSec
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-04-10 22:16:21 UTC
Updated2026-04-10 22:16:21 UTC
DescriptionNet::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.

Risk And Classification

Problem Types: CWE-130 | CWE-130 CWE-130 Improper Handling of Length Parameter Inconsistency

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA STIGTSP NetCIDRLite affected 0.23 custom Not specified

References

ReferenceSourceLinkTags
github.com/stigtsp/Net-CIDR-Lite/commit/b7166b1fa17b3b14b4c795ace5b3fbf7... 9b29abf9-4ab0-4765-b253-1875cd9b441e github.com
www.cve.org/CVERecord 9b29abf9-4ab0-4765-b253-1875cd9b441e www.cve.org
metacpan.org/release/STIGTSP/Net-CIDR-Lite-0.23/changes 9b29abf9-4ab0-4765-b253-1875cd9b441e metacpan.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Additional Advisory Data

SourceTimeEvent
CNA2026-04-09T00:00:00.000ZVulnerability found
CNA2026-04-10T00:00:00.000ZNet-CIDR-Lite version 0.23 released

Solutions

CNA: Upgrade to version 0.23 or newer, or apply the patch provided.

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