{"id":"CVE-2026-93009","state":"PUBLISHED","title":"Dnsmasq: dnsmasq: heap out-of-bounds read in dhcpv6 option 39 fqdn decoder","description":"A flaw was found in dnsmasq. The DHCPv6 client hostname parser can read one byte past the end of a crafted FQDN option because it checks the next label length before confirming the pointer is still inside the option. An attacker on the local network can trigger this with a single DHCPv6 packet. The extra byte is not returned to the client or logged, and no crash has been demonstrated.","publishedAt":"2026-10-29T13:13:34.504Z","updatedAt":"2026-10-30T08:05:48.784Z","severity":{"score":4.3,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","source":"redhat"},"assigner":"redhat","products":["Red Hat Red Hat Ceph Storage 9","Red Hat Red Hat Enterprise Linux 10","Red Hat Red Hat Enterprise Linux 6","Red Hat Red Hat Enterprise Linux 7","Red Hat Red Hat Enterprise Linux 8","Red Hat Red Hat Enterprise Linux 9","Red Hat Red Hat OpenShift Container Platform 4","Red Hat Red Hat OpenShift Container Platform 5","Red Hat Red Hat OpenStack Platform 13 (Queens)","Red Hat Red Hat OpenStack Platform 18.0"],"affected":[{"vendor":"Red Hat","product":"Red Hat Ceph Storage 9","packageName":"rhceph/alloy-rhel10","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:ceph_storage:9"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 10","packageName":"dnsmasq","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:10"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 6","packageName":"dnsmasq","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:6"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 7","packageName":"dnsmasq","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:7"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 8","packageName":"dnsmasq","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:8"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","packageName":"dnsmasq","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:9"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","packageName":"openshift4/ose-baremetal-runtimecfg-rhel8","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openshift:4"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","packageName":"openshift4/ose-baremetal-runtimecfg-rhel9","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openshift:4"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","packageName":"openshift/ose-rhel-coreos-8","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openshift:4"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","packageName":"openshift/ose-rhel-coreos-9","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openshift:4"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 5","packageName":"openshift5/ose-baremetal-runtimecfg-rhel9","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openshift:5"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 5","packageName":"openshift/ose-rhel-coreos-9","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openshift:5"]},{"vendor":"Red Hat","product":"Red Hat OpenStack Platform 13 (Queens)","packageName":"dnsmasq","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openstack:13"]},{"vendor":"Red Hat","product":"Red Hat OpenStack Platform 18.0","packageName":"rhoso-operators/infra-rhel9-operator","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openstack:18.0"]}],"references":["https://access.redhat.com/security/cve/CVE-2026-93009","https://bugzilla.redhat.com/show_bug.cgi?id=2536083"],"weaknesses":["CWE-125"],"ingestedAt":"2026-10-30T08:12:06.012Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/93xxx/CVE-2026-93009.json","commit":"f6947265cbc73919816794b1f4d4d1f391dc8531","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-93009","state":"PUBLISHED","datePublished":"2026-10-29T13:13:34.504Z","dateUpdated":"2026-10-30T08:05:48.784Z","assignerShortName":"redhat","assignerOrgId":"53f830b8-0a3f-465b-8143-3b8a9948e749","dateReserved":"2026-09-17T14:35:34.562Z"},"containers":{"cna":{"title":"Dnsmasq: dnsmasq: heap out-of-bounds read in dhcpv6 option 39 fqdn decoder","descriptions":[{"lang":"en","value":"A flaw was found in dnsmasq. The DHCPv6 client hostname parser can read one byte past the end of a crafted FQDN option because it checks the next label length before confirming the pointer is still inside the option. An attacker on the local network can trigger this with a single DHCPv6 packet. The extra byte is not returned to the client or logged, and no crash has been demonstrated."}],"affected":[{"vendor":"Red Hat","product":"Red Hat Ceph Storage 9","packageName":"rhceph/alloy-rhel10","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:ceph_storage:9"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 10","packageName":"dnsmasq","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:10"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 6","packageName":"dnsmasq","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:6"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 7","packageName":"dnsmasq","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:7"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 8","packageName":"dnsmasq","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:8"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","packageName":"dnsmasq","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:9"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","packageName":"openshift4/ose-baremetal-runtimecfg-rhel8","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openshift:4"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","packageName":"openshift4/ose-baremetal-runtimecfg-rhel9","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openshift:4"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","packageName":"openshift/ose-rhel-coreos-8","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openshift:4"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","packageName":"openshift/ose-rhel-coreos-9","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openshift:4"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 5","packageName":"openshift5/ose-baremetal-runtimecfg-rhel9","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openshift:5"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 5","packageName":"openshift/ose-rhel-coreos-9","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openshift:5"]},{"vendor":"Red Hat","product":"Red Hat OpenStack Platform 13 (Queens)","packageName":"dnsmasq","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openstack:13"]},{"vendor":"Red Hat","product":"Red Hat OpenStack Platform 18.0","packageName":"rhoso-operators/infra-rhel9-operator","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openstack:18.0"]}],"references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-93009","tags":["vdb-entry","x_refsource_REDHAT"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2536083","name":"RHBZ#2536083","tags":["issue-tracking","x_refsource_REDHAT"]}],"metrics":[{"other":{"content":{"value":"Low","namespace":"https://access.redhat.com/security/updates/classification/"},"type":"Red Hat severity rating"}},{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"ADJACENT_NETWORK","availabilityImpact":"NONE","baseScore":4.3,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","version":"3.1"},"format":"CVSS"}],"problemTypes":[{"descriptions":[{"cweId":"CWE-125","description":"Out-of-bounds Read","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"redhat","orgId":"53f830b8-0a3f-465b-8143-3b8a9948e749","dateUpdated":"2026-10-30T08:05:48.784Z"},"datePublic":"2026-10-28T09:30:00.000Z","x_redhatCweChain":"CWE-125: Out-of-bounds Read","workarounds":[{"lang":"en","value":"The following measures reduce risk:\n\n1. If DHCPv6 is not required, do not configure any IPv6 dhcp-range.\n2. Compile without DHCPv6 using COPTS=-DNO_DHCP6 if IPv6 DHCP is not needed.\n3. Restrict dnsmasq to trusted interfaces with --interface=<iface>."}],"timeline":[{"lang":"en","time":"2026-09-14T00:00:00.000Z","value":"Reported to Red Hat."},{"lang":"en","time":"2026-10-28T09:30:00.000Z","value":"Made public."}],"credits":[{"lang":"en","value":"Red Hat would like to thank Shubham Raj (Causal Security) for reporting this issue."}],"x_generator":{"engine":"cvelib 1.8.0"}}}}}