CVE-2026-6507: Dnsmasq: dnsmasq: denial of service due to out-of-bounds write in dhcp bootreply processing

Severity: high (CVSS 7.5 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: 2026-04-17 · updated 2026-10-25
Weakness: CWE-787

Description

A 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).

References

https://access.redhat.com/security/cve/CVE-2026-6507
https://bugzilla.redhat.com/show_bug.cgi?id=2459181

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