CVE-2026-6507

NameCVE-2026-6507
DescriptionA flaw was found in dnsmasq. A remote attacker could exploit an out-of-bounds write vulnerability by sending a specially crafted BOOTREPLY (Bootstrap Protocol Reply) packet to a dnsmasq server configured with the `--dhcp-split-relay` option. This can lead to memory corruption, causing the dnsmasq daemon to crash and resulting in a denial of service (DoS).
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs1134264

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
dnsmasq (PTS)bullseye2.85-1fixed
bullseye (security)2.85-1+deb11u1fixed
bookworm2.90-4~deb12u1fixed
trixie2.91-1fixed
forky, sid2.92-4fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
dnsmasqsourcebullseye(not affected)
dnsmasqsourcebookworm(not affected)
dnsmasqsourcetrixie(not affected)
dnsmasqsource(unstable)2.92-41134264

Notes

[trixie] - dnsmasq <not-affected> (Vulnerable code introduced later)
[bookworm] - dnsmasq <not-affected> (Vulnerable code introduced later)
[bullseye] - dnsmasq <not-affected> (Vulnerable code introduced later)
https://bugzilla.redhat.com/show_bug.cgi?id=2459181
Introduced with: https://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commitdiff;h=1677c6e10b81d4e1181e3a3f88e738ea6d69be8a (v2.92test20)
Fixed by: https://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commitdiff;h=9ad74926d4f7f34ff902e1db5235535aa813c33f (v2.93test9)

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