==========================================================================
Ubuntu Security Notice USN-8406-1
June 08, 2026

libnet-cidr-lite-perl vulnerabilities
==========================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 26.04 LTS
- Ubuntu 25.10
- Ubuntu 24.04 LTS
- Ubuntu 22.04 LTS
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

Several security issues were fixed in Net::CIDR::Lite.

Software Description:
- libnet-cidr-lite-perl: module for merging IPv4 or IPv6 CIDR address ranges

Details:

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)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 26.04 LTS
  libnet-cidr-lite-perl           0.22-2ubuntu0.26.04.1

Ubuntu 25.10
  libnet-cidr-lite-perl           0.22-2ubuntu0.25.10.1

Ubuntu 24.04 LTS
  libnet-cidr-lite-perl           0.22-2ubuntu0.24.04.1

Ubuntu 22.04 LTS
  libnet-cidr-lite-perl           0.22-1ubuntu0.1

Ubuntu 20.04 LTS
  libnet-cidr-lite-perl           0.21-2ubuntu0.1+esm1
                                  Available with Ubuntu Pro

Ubuntu 18.04 LTS
  libnet-cidr-lite-perl           0.21-1ubuntu0.18.04.1~esm1
                                  Available with Ubuntu Pro

Ubuntu 16.04 LTS
  libnet-cidr-lite-perl           0.21-1ubuntu0.16.04.1~esm1
                                  Available with Ubuntu Pro

In general, a standard system update will make all the necessary changes.

References:
  https://ubuntu.com/security/notices/USN-8406-1
  CVE-2021-47154, CVE-2026-40198, CVE-2026-40199

Package Information:
  https://launchpad.net/ubuntu/+source/libnet-cidr-lite-perl/0.22-2ubuntu0.26.04.1
  https://launchpad.net/ubuntu/+source/libnet-cidr-lite-perl/0.22-2ubuntu0.25.10.1
  https://launchpad.net/ubuntu/+source/libnet-cidr-lite-perl/0.22-2ubuntu0.24.04.1
  https://launchpad.net/ubuntu/+source/libnet-cidr-lite-perl/0.22-1ubuntu0.1