{"id":"AZL-87027","summary":"CVE-2026-33278 affecting package unbound for versions less than 1.25.1-1","details":"NLnet Labs Unbound 1.19.1 up to and including version 1.25.0 has a vulnerability in the DNSSEC validator that enables denial of service and possible remote code execution as a result of deep copying a data structure and erroneously overwriting a destination pointer. An adversary can exploit the vulnerability by controlling a malicious signed zone and querying a vulnerable Unbound. When DS sub-queries need to suspend validation due to NSEC3 computational budget exhaustion (introduced in Unbound 1.19.1), Unbound deep-copies response messages to preserve them across memory region teardown. A struct-assignment bug overwrites the destination's pointer with the source's pointer. After the sub-query region is freed, the resumed validator dereferences this dangling pointer, triggering a crash or potentially enabling arbitrary code execution. Unbound 1.25.1 contains a patch with a fix to preserve the correct pointer when deep copying the data structure.","modified":"2026-08-28T17:48:00.355073964Z","published":"2026-05-20T10:16:26Z","upstream":["CVE-2026-33278"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33278"}],"affected":[{"package":{"name":"unbound","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/unbound"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.25.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-87027.json"}}],"schema_version":"1.9.0"}