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.

The remote Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-8406-1 advisory.

    Dave Rolsky discovered that Net::CIDR::Lite did not properly handle extraneous zero characters at the     beginning of an IP address string. A remote attacker could possibly use this issue to bypass access     controls that are based on IP addresses. This issue only affected Ubuntu 16.04 LTS and Ubuntu 18.04 LTS.
    (CVE-2021-47154)

    It was discovered that Net::CIDR::Lite did not properly validate the IPv6 group count when handling     uncompressed IPv6 addresses. A remote attacker could possibly use this issue to bypass access controls.
    (CVE-2026-40198)

    It was discovered that Net::CIDR::Lite mishandled IPv4 mapped IPv6 addresses. A remote attacker could     possibly use this issue to bypass access controls that are based on IP addresses. (CVE-2026-40199)

Tenable has extracted the preceding description block directly from the Ubuntu 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 SUSE Linux SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 host has a package installed that is affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:2113-1 advisory.

    This update for perl-Net-CIDR-Lite fixes the following issues

    - CVE-2026-45190: improper validation of trailing newlines or non-ASCII digits can lead to IP ACL bypass     (bsc#1264710).
    - CVE-2026-45191: extraneous leading zeros in CIDR mask values can lead to IP ACL bypass (bsc#1264709).
    - CVE-2026-40198: missing validation for the IPv6 group count can lead to IP ACL bypass (bsc#1262088).
    - CVE-2026-40199: mishandled IPv4 mapped IPv6 addresses can lead to IP ACL bypass (bsc#1262088).

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

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

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.

There are packages installed that are affected by multiple vulnerabilities referenced in the following CVEs:

  - 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)

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
320398	Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS : Net::CIDR::Lite vulnerabilities (USN-8406-1)	Nessus	Ubuntu Local Security Checks	high
319663	SUSE SLED15 / SLES15 Security Update : perl-Net-CIDR-Lite (SUSE-SU-2026:2113-1)	Nessus	SuSE Local Security Checks	high
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
440288	Alpine: perl-net-cidr-lite: security update to 0.23-r0	Tenable Cloud Security	Alpine Linux Local Security Checks	high
440288	Alpine: perl-net-cidr-lite: security update to 0.23-r0	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	high
306020	Linux Distros Unpatched Vulnerability : CVE-2026-40199	Nessus	Misc.	medium

Detections

Analytics

CVE-2026-40199

medium

Tenable Plugins

high

high

high

high

high

high

high

high

medium