NSD vulnerabilities

Summary

It was discovered that NSD incorrectly handled APL resource records with an address length larger than permitted for the address family. A remote attacker could use this to cause a stack-based buffer overflow when the zone is written to disk, potentially executing arbitrary code with the privileges of the NSD server. (CVE-2026-12246) It was discovered that NSD incorrectly handled SVCB resource records. A remote attacker could use this to cause a heap overflow, potentially executing arbitrary code with the privileges of the NSD server. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-12244) It was discovered that NSD had a use-after-free vulnerability in TLS connection error logging. A remote attacker could use this to cause a denial of service by crashing the server process. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-12245) It was discovered that NSD incorrectly handled TLS authentication for zone transfers. An attacker could bypass transfer security restrictions when certain conditions were met. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-12490) Affected Ubuntu releases: 26.04, 24.04, 22.04, 20.04, 18.04, 16.04. CVEs: CVE-2026-12490, CVE-2026-12245, CVE-2026-12244, CVE-2026-12246.