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Vulnerability · Published Jun 22, 2026 · Assigned by redhat

CVE-2026-12725Dnsmasq: dnsmasq: heap buffer overflow in log_query() when logging unsupported ds/dnskey replies

Medium 5.9

In plain English

A medium-severity heap buffer overflow in Red Hat Enterprise Linux 10 from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 45% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.9Medium
Exploit odds (30 days)0.5%top 55.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

A heap-based buffer overflow was found in dnsmasq. When DNSSEC validation and query logging are both enabled, logging of DS or DNSKEY replies containing unsupported algorithm or digest types can cause dnsmasq to write past the end of an internal logging buffer. A remote attacker able to supply such a DNS response may crash the dnsmasq process, resulting in denial of service.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12dnsmasqno fix listedDEBIAN-CVE-2026-12725
Debian:13dnsmasq2.91-1+deb13u2DEBIAN-CVE-2026-12725
Debian:14dnsmasq2.93-1DEBIAN-CVE-2026-12725
Ubuntu:22.04:LTSdnsmasq2.90-0ubuntu0.22.04.4USN-8542-1
Ubuntu:22.04:LTSdnsmasq2.90-0ubuntu0.22.04.4UBUNTU-CVE-2026-12725
Ubuntu:24.04:LTSdnsmasq2.90-2ubuntu0.4USN-8542-1
Ubuntu:24.04:LTSdnsmasq2.90-2ubuntu0.4UBUNTU-CVE-2026-12725
Ubuntu:25.10dnsmasqno fix listedUBUNTU-CVE-2026-12725
Ubuntu:26.04:LTSdnsmasq2.92-1ubuntu0.4UBUNTU-CVE-2026-12725
Ubuntu:26.04:LTSdnsmasq2.92-1ubuntu0.4USN-8542-1

Affected products (as reported)

VendorProductVersions
Red Hat Red Hat Enterprise Linux 10 see references
Red Hat Red Hat Enterprise Linux 6 see references
Red Hat Red Hat Enterprise Linux 7 see references
Red Hat Red Hat Enterprise Linux 8 see references
Red Hat Red Hat Enterprise Linux 9 see references
Red Hat Red Hat OpenShift Container Platform 4 see references
Red Hat Red Hat OpenShift Container Platform 4 see references
Red Hat Red Hat OpenShift Container Platform 5 see references

Weakness: CWE-122 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

References