========================================================================== Ubuntu Security Notice USN-8110-1 March 18, 2026
libnet-cidr-perl vulnerability
==========================================================================
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 24.04 LTS
- Ubuntu 22.04 LTS
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
- Ubuntu 14.04 LTS
Summary:
Net-CIDR could allow unintended access to network services.
Software Description:
- libnet-cidr-perl: module for merging IPv4 or IPv6 CIDR address ranges
Details:
Dave Rolsky discovered that Net-CIDR did not properly sanitize IP
addresses. An attacker could possibly use this to bypass IP-based
restrictions.
Update instructions:
The problem can be corrected by updating your system to the following
package versions:
Ubuntu 24.04 LTS
libnet-cidr-perl 0.21-2ubuntu0.2
Ubuntu 22.04 LTS
libnet-cidr-perl 0.21-1ubuntu0.2
Ubuntu 20.04 LTS
libnet-cidr-perl 0.20-1ubuntu0.1~esm2
Available with Ubuntu Pro
Ubuntu 18.04 LTS
libnet-cidr-perl 0.18-1ubuntu0.1~esm2
Available with Ubuntu Pro
Ubuntu 16.04 LTS
libnet-cidr-perl 0.17-1ubuntu0.16.04.1~esm2
Available with Ubuntu Pro
Ubuntu 14.04 LTS
libnet-cidr-perl 0.17-1ubuntu0.14.04.1~esm2
Available with Ubuntu Pro
In general, a standard system update will make all the necessary changes.
References:
https://ubuntu.com/security/notices/USN-8110-1
CVE-2021-4456
Package Information:
https://launchpad.net/ubuntu/+source/libnet-cidr-perl/0.21-2ubuntu0.2
https://launchpad.net/ubuntu/+source/libnet-cidr-perl/0.21-1ubuntu0.2
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