Multiple Vulnerabilities in Net::CIDR::Lite Affect Ubuntu Releases

• •Net::CIDR::Lite vulnerabilities allow IP access control bypass.
• •Affected Ubuntu versions include 16.04 LTS and 18.04 LTS.
• •Users should update to the latest package versions to mitigate risks.

Multiple vulnerabilities were discovered in the Net::CIDR::Lite module, affecting various Ubuntu versions, including 16.04 LTS and 18.04 LTS. The vulnerabilities allow remote attackers to bypass access controls based on IP addresses. Specifically, CVE-2021-47154 involves mishandling of extraneous zero characters in IP address strings, while CVE-2026-40198 and CVE-2026-40199 pertain to improper validation of IPv6 addresses and mishandling of IPv4 mapped IPv6 addresses, respectively. The issues were reported by Dave Rolsky and are critical for systems relying on IP-based access controls. Users are advised to update their systems to mitigate these vulnerabilities. The vulnerabilities were published on April 10, 2026, and March 18, 2024, respectively. The affected systems include Ubuntu 16.04 LTS, 18.04 LTS, and other versions.