Critical Samba Vulnerabilities Affect Multiple Ubuntu Releases

On May 26, 2026, multiple vulnerabilities in Samba were disclosed, affecting Ubuntu 24.04 LTS, 25.10, and 26.04 LTS. Key issues include improper handling of access checks on reparse point operations (CVE-2026-1933), which could allow modification of read-only files, and a failure to block file overwrites in Samba's vfs_worm module (CVE-2026-2340). Additionally, a machine-in-the-middle attack could exploit Samba's handling of certificate auto-enrolment group policies (CVE-2026-3012). A denial of service vulnerability was also identified in Samba's Active Directory Domain Controller (CVE-2026-3238). Users are advised to update their systems to mitigate these risks. The vulnerabilities are considered critical due to their potential impact on system integrity and security.

Key Points: • Samba vulnerabilities affect Ubuntu 24.04 LTS, 25.10, and 26.04 LTS. • CVE-2026-1933 allows modification of read-only files via improper access checks. • Immediate updates are recommended to address these critical vulnerabilities.