Out-of-bounds Read Affecting dnsmasq package, versions <2.90-0ubuntu0.20.04.1+esm3


Severity

Recommended
0.0
medium
0
10

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.24% (15th percentile)

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  • Snyk IDSNYK-UBUNTU2004-DNSMASQ-17442406
  • published14 Jul 2026
  • disclosed23 Jun 2026

Introduced: 23 Jun 2026

CVE-2026-12969  (opens in a new tab)
CWE-125  (opens in a new tab)

How to fix?

Upgrade Ubuntu:20.04 dnsmasq to version 2.90-0ubuntu0.20.04.1+esm3 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream dnsmasq package and not the dnsmasq package as distributed by Ubuntu. See How to fix? for Ubuntu:20.04 relevant fixed versions and status.

An out-of-bounds read vulnerability exists in dnsmasq's find_soa() function in src/rfc1035.c. When parsing NS section records, extract_name() is called with extrabytes=0, failing to validate that 10 additional bytes exist for fixed-length DNS record fields. A remote attacker controlling a DNS zone can exploit this via a crafted NXDOMAIN response to cause a 10-byte heap out-of-bounds read, potentially accessing stale data from prior transactions.

CVSS Base Scores

version 3.1