========================================================================== Ubuntu Security Notice USN-8282-1 May 20, 2026
unbound vulnerabilities ========================================================================== A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 26.04 LTS - Ubuntu 25.10 - Ubuntu 24.04 LTS - Ubuntu 22.04 LTS Summary: Several security issues were fixed in Unbound. Software Description: - unbound: validating, recursive, caching DNS resolver Details: 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) Update instructions: The problem can be corrected by updating your system to the following package versions: Ubuntu 26.04 LTS libunbound8 1.24.2-1ubuntu2.1 unbound 1.24.2-1ubuntu2.1 Ubuntu 25.10 libunbound8 1.22.0-2ubuntu2.3 unbound 1.22.0-2ubuntu2.3 Ubuntu 24.04 LTS libunbound8 1.19.2-1ubuntu3.8 unbound 1.19.2-1ubuntu3.8 Ubuntu 22.04 LTS libunbound8 1.13.1-1ubuntu5.15 unbound 1.13.1-1ubuntu5.15 In general, a standard system update will make all the necessary changes. References: https://ubuntu.com/security/notices/USN-8282-1 CVE-2026-32792, CVE-2026-33278, CVE-2026-40622, CVE-2026-41292, CVE-2026-42534, CVE-2026-42923, CVE-2026-42944, CVE-2026-42959, CVE-2026-42960, CVE-2026-44390, CVE-2026-44608 Package Information: https://launchpad.net/ubuntu/+source/unbound/1.24.2-1ubuntu2.1 https://launchpad.net/ubuntu/+source/unbound/1.22.0-2ubuntu2.3 https://launchpad.net/ubuntu/+source/unbound/1.19.2-1ubuntu3.8 https://launchpad.net/ubuntu/+source/unbound/1.13.1-1ubuntu5.15
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