Critical Vulnerabilities in Ubuntu 20.04 LTS Linux Kernel Addressed

Severity: High (Score: 74.0)

Sources: Ubuntu, Linuxsecurity

Summary

On May 11, 2026, Ubuntu released USN-8255-2, addressing multiple vulnerabilities in the Linux kernel, particularly affecting the OverlayFS implementation. Discovered by researchers Stonejiajia, Shir Tamari, and Sagi Tzadik, these vulnerabilities (CVE-2023-2640 and CVE-2023-32629) could allow local attackers to gain elevated privileges. Additionally, flaws in network and NVME drivers were identified (CVE-2026-23112 and CVE-2026-23273), posing risks of system compromise. Users are advised to update to the latest kernel versions to mitigate these risks. The vulnerabilities were published between February and March 2026, with proof-of-concept exploits available for some. Affected systems include Ubuntu 20.04 LTS running the Linux kernel for Microsoft Azure cloud systems. Immediate action is recommended to prevent potential exploitation. Key Points: • Multiple critical vulnerabilities in the Ubuntu Linux kernel have been identified and patched. • Local attackers could exploit these vulnerabilities to gain elevated privileges. • Users must update their systems to the latest kernel versions to mitigate risks.

Key Entities

• Zero-day Exploit (attack_type)
• CVE-2023-2640 (cve)
• CVE-2023-32629 (cve)
• CVE-2026-23112 (cve)
• CVE-2026-23273 (cve)
• CWE-269 - Improper Privilege Management (cwe)
• T1068 - Exploitation for Privilege Escalation (mitre_attack)
• Azure (company)
• Ubuntu (company)
• Linux (platform)