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.
Published: 2026-10-29
Score: 4.3 Medium
EPSS: n/a
KEV: No
AI Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Remediation

Vendor Workaround

The following measures reduce risk: 1. If DHCPv6 is not required, do not configure any IPv6 dhcp-range. 2. Compile without DHCPv6 using COPTS=-DNO_DHCP6 if IPv6 DHCP is not needed. 3. Restrict dnsmasq to trusted interfaces with --interface=<iface>.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

History

Thu, 29 Oct 2026 13:30:00 +0000

Type Values Removed Values Added
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.
Title Dnsmasq: dnsmasq: heap out-of-bounds read in dhcpv6 option 39 fqdn decoder
First Time appeared Redhat
Redhat ceph Storage
Redhat enterprise Linux
Redhat openshift
Redhat openstack
Weaknesses CWE-125
CPEs cpe:/a:redhat:ceph_storage:9
cpe:/a:redhat:openshift:4
cpe:/a:redhat:openstack:13
cpe:/a:redhat:openstack:18.0
cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat ceph Storage
Redhat enterprise Linux
Redhat openshift
Redhat openstack
References
Metrics cvssV3_1

{'score': 4.3, 'vector': 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N'}


Subscriptions

Redhat Ceph Storage Enterprise Linux Openshift Openstack
cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-10-29T13:13:34.504Z

Reserved: 2026-09-17T14:35:34.562Z

Link: CVE-2026-93009

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-10-29T14:18:00.367

Modified: 2026-10-29T14:18:00.480

Link: CVE-2026-93009

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses