CVE-2026-93009 Dnsmasq: dnsmasq: heap out-of-bounds read in dhcpv6 option 39 fqdn decoder
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-93009?
CVE-2026-93009 is a medium-severity vulnerability in Red Hat Ceph Storage 9, published on 29 Oct 2026.
Official description
A flaw was found in dnsmasq. The DHCPv6 client hostname parser can read one byte past the end of a crafted FQDN option because it checks the next label length before confirming the pointer is still inside the option. An attacker on the local network can trigger this with a single DHCPv6 packet. The extra byte is not returned to the client or logged, and no crash has been demonstrated.
Weakness: CWE-125
Which versions are affected by CVE-2026-93009?
How do I fix CVE-2026-93009?
No fix has been published for CVE-2026-93009 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-93009 being exploited?
There is no known exploitation of CVE-2026-93009 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-93009, GHSA-6qrc-rpqw-59wp.