{"id":"ALSA-2026:20589","summary":"Important: dnsmasq security update","details":"The dnsmasq packages contain Dnsmasq, a lightweight DNS (Domain Name Server) forwarder and DHCP (Dynamic Host Configuration Protocol) server.  \n\nSecurity Fix(es):  \n\n  * dnsmasq: dnsmasq: heap buffer overflow in cache via NAME_ESCAPE expansion (CVE-2026-2291)\n  * dnsmasq: NSEC bitmap parsing infinite loop (CVE-2026-4890)\n  * dnsmasq: RRSIG rdlen underflow leading to heap OOB read (CVE-2026-4891)\n  * dnsmasq: DHCPv6 CLID buffer overflow in helper process (CVE-2026-4892)\n  * dnsmasq: Broken ECS source validation bypass (CVE-2026-4893)\n\n\nFor more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.\n","modified":"2026-05-26T15:30:03.774233596Z","published":"2026-05-26T00:00:00Z","related":["CVE-2026-2291","CVE-2026-4890","CVE-2026-4891","CVE-2026-4892","CVE-2026-4893"],"references":[{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:20589"},{"type":"REPORT","url":"https://access.redhat.com/security/cve/CVE-2026-2291"},{"type":"REPORT","url":"https://access.redhat.com/security/cve/CVE-2026-4890"},{"type":"REPORT","url":"https://access.redhat.com/security/cve/CVE-2026-4891"},{"type":"REPORT","url":"https://access.redhat.com/security/cve/CVE-2026-4892"},{"type":"REPORT","url":"https://access.redhat.com/security/cve/CVE-2026-4893"},{"type":"REPORT","url":"https://bugzilla.redhat.com/2439088"},{"type":"REPORT","url":"https://bugzilla.redhat.com/2458516"},{"type":"REPORT","url":"https://bugzilla.redhat.com/2458517"},{"type":"REPORT","url":"https://bugzilla.redhat.com/2458518"},{"type":"REPORT","url":"https://bugzilla.redhat.com/2458519"},{"type":"ADVISORY","url":"https://errata.almalinux.org/8/ALSA-2026-20589.html"}],"affected":[{"package":{"name":"dnsmasq","ecosystem":"AlmaLinux:8","purl":"pkg:rpm/almalinux/dnsmasq"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.79-36.el8_10"}]}],"database_specific":{"source":"https://github.com/AlmaLinux/osv-database/blob/master/advisories/almalinux8/ALSA-2026:20589.json"}},{"package":{"name":"dnsmasq-utils","ecosystem":"AlmaLinux:8","purl":"pkg:rpm/almalinux/dnsmasq-utils"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.79-36.el8_10"}]}],"database_specific":{"source":"https://github.com/AlmaLinux/osv-database/blob/master/advisories/almalinux8/ALSA-2026:20589.json"}}],"schema_version":"1.7.5"}