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.

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-1624 advisory.

    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.
    (CVE-2026-40198)

    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.
    (CVE-2026-40199)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Fedora 44 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-fe487aa625 advisory.

    This update addresses two security issues regarding incorrect handling of malformed IPv6 addresses:

     * Fix IPv4 mapped IPv6 packed length (CVE-2026-40199)
     * Reject invalid uncompressed IPv6 (CVE-2026-40198)

Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Fedora 42 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-4b112416d8 advisory.

    This update addresses two security issues regarding incorrect handling of malformed IPv6 addresses:

     * Fix IPv4 mapped IPv6 packed length (CVE-2026-40199)
     * Reject invalid uncompressed IPv6 (CVE-2026-40198)

Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Fedora 43 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-0a7ed21996 advisory.

    This update addresses two security issues regarding incorrect handling of malformed IPv6 addresses:

     * Fix IPv4 mapped IPv6 packed length (CVE-2026-40199)
     * Reject invalid uncompressed IPv6 (CVE-2026-40198)

Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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. (CVE-2026-40199)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Severity
311311	Amazon Linux 2023 : perl-Net-CIDR-Lite (ALAS2023-2026-1624)	Nessus	Amazon Linux Local Security Checks	high
310221	Fedora 44 : perl-Net-CIDR-Lite (2026-fe487aa625)	Nessus	Fedora Local Security Checks	high
309196	Fedora 42 : perl-Net-CIDR-Lite (2026-4b112416d8)	Nessus	Fedora Local Security Checks	high
307660	Fedora 43 : perl-Net-CIDR-Lite (2026-0a7ed21996)	Nessus	Fedora Local Security Checks	high
306020	Linux Distros Unpatched Vulnerability : CVE-2026-40199	Nessus	Misc.	medium

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