[<prev] [next>] [day] [month] [year] [list]
Message-ID: <adlwk7KgpcptKJUC@ava>
Date: Fri, 10 Apr 2026 23:53:28 +0200
From: Stig Palmquist <stig@...g.io>
To: cve-announce@...urity.metacpan.org, oss-security@...ts.openwall.com
Subject: CVE-2026-40199: Net::CIDR::Lite versions before 0.23 for Perl
mishandles IPv4 mapped IPv6 addresses, which may allow IP ACL bypass
========================================================================
CVE-2026-40199 CPAN Security Group
========================================================================
CVE ID: CVE-2026-40199
Distribution: Net-CIDR-Lite
Versions: before 0.23
MetaCPAN: https://metacpan.org/dist/Net-CIDR-Lite
VCS Repo: https://github.com/stigtsp/Net-CIDR-Lite
Net::CIDR::Lite versions before 0.23 for Perl mishandles IPv4 mapped
IPv6 addresses, which may allow IP ACL bypass
Description
-----------
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.
Problem types
-------------
- CWE-130 Improper Handling of Length Parameter Inconsistency
Solutions
---------
Upgrade to version 0.23 or newer, or apply the patch provided.
References
----------
https://github.com/stigtsp/Net-CIDR-Lite/commit/b7166b1fa17b3b14b4c795ace5b3fbf71a0bd04a.patch
https://metacpan.org/release/STIGTSP/Net-CIDR-Lite-0.23/changes
https://www.cve.org/CVERecord?id=CVE-2026-40198
Timeline
--------
- 2026-04-09: Vulnerability found
- 2026-04-10: Net-CIDR-Lite version 0.23 released
Powered by blists - more mailing lists
Please check out the
Open Source Software Security Wiki, which is counterpart to this
mailing list.
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
