CVE-2026-12969

Publication date 23 June 2026

Last updated 16 July 2026

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

5.3 · Medium

Score breakdown

Description

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.

Status

Package Ubuntu Release Status
dnsmasq 26.04 LTS resolute
Fixed 2.92-1ubuntu0.4
25.10 questing Ignored end of life, was needs-triage
24.04 LTS noble
Fixed 2.90-2ubuntu0.4
22.04 LTS jammy
Fixed 2.90-0ubuntu0.22.04.4
20.04 LTS focal
Fixed 2.90-0ubuntu0.20.04.1+esm3
18.04 LTS bionic
Fixed 2.90-0ubuntu0.18.04.1+esm4
16.04 LTS xenial
Fixed 2.90-0ubuntu0.16.04.1+esm4
14.04 LTS trusty
Not affected

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Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
dnsmasq

Severity score breakdown

CVSS version: CVSS v3.0

Base score 5.3 · Medium

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

References

Related Ubuntu Security Notices (USN)

Other references

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