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

Severity: medium (CVSS 5.9 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-22 · updated 2026-08-31
Weakness: CWE-122

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 products

Red Hat Enterprise Linux: 8.0, 9.0, 10.0
Red Hat OpenShift Container Platform 4.18: from 4.0 through 4.22.1
Simon Kelley dnsmasq: before 2.93 — fixed in 2.93

How to fix

Upgrade to a fixed version: Simon Kelley dnsmasq 2.93. Check the vendor advisory for mitigations.

References

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