Multiple vulnerabilities in Unbound allow remote attackers to cause denial of service via malformed DNSCrypt packets, excessive resource consumption via long EDNS option lists or unbounded NSEC3 hash calculations, and in specific cases, execute arbitrary code via DNSSEC validation flaws or use-after-free in RPZ handling. The CVSS scores and specific affected version ranges are not provided in the source material. The vulnerabilities affect various Ubuntu LTS releases, with some issues specific to Ubuntu 24.04 LTS, 25.10, and 26.04 LTS.
Andrew Griffiths discovered that Unbound did not properly handle certain DNSCrypt packets. A remote attacker could possibly use this issue to cause Unbound to crash, resulting in a denial of service. (CVE-2026-32792) Qifan Zhang discovered that Unbound incorrectly handled DNSSEC validation in certain situations. A remote attacker could possibly use this issue to execute arbitrary code. This issue only affected Ubuntu 24.04 LTS, Ubuntu 25.10, and Ubuntu 26.04 LTS. (CVE-2026-33278) Qifan Zhang discovered that Unbound incorrectly handled certain ghost domain name records. A remote attacker could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 24.04 LTS, Ubuntu 25.10, and Ubuntu 26.04 LTS. (CVE-2026-40622) Qifan Zhang discovered that Unbound did not properly limit processing of long EDNS option lists. A remote attacker could possibly use this issue to cause Unbound to use excessive resources, leading to a denial of service. (CVE-2026-41292) Qifan Zhang discovered that Unbound incorrectly handled jostle logic under certain circumstances. A remote attacker could possibly use this issue to cause Unbound to use excessive resources, leading to a denial of service. (CVE-2026-42534) Qifan Zhang discovered that Unbound did not properly bound NSEC3 hash calculations. A remote attacker could possibly use this issue to cause Unbound to use excessive resources, leading to a denial of service. (CVE-2026-42923) Qifan Zhang discovered that Unbound incorrectly handled multiple EDNS options in certain situations. A remote attacker could possibly use this issue to cause Unbound to crash, resulting in a denial of service, or execute arbitrary code. This issue only affected Ubuntu 24.04 LTS, Ubuntu 25.10, and Ubuntu 26.04 LTS. (CVE-2026-42944) Qifan Zhang discovered that Unbound incorrectly handled DNSSEC validation of malicious content. A remote attacker could possibly use this issue to cause Unbound to crash, resulting in a denial of service. (CVE-2026-42959) TaoFei Guo, Yang Luo, and JianJun Chen discovered that Unbound incorrectly handled delegation processing in certain situations. A remote attacker could possibly use this issue to poison the DNS cache and obtain sensitive information. (CVE-2026-42960) Qifan Zhang discovered that Unbound did not properly bound name compression in certain cases. A remote attacker could possibly use this issue to cause Unbound to use excessive resources, leading to a denial of service. (CVE-2026-44390) Qifan Zhang discovered that Unbound had a use-after-free issue in RPZ handling. A remote attacker could possibly use this issue to cause Unbound to crash, resulting in a denial of service, or execute arbitrary code. This issue only affected Ubuntu 24.04 LTS, Ubuntu 25.10, and Ubuntu 26.04 LTS. (CVE-2026-44608)