Dnsmasq: dnsmasq: heap out-of-bounds read in dhcpv6 option 39 fqdn decoder
Historical advisory recorded 30 Oct 2026 09:48:55 UTC. Read the latest advisory.
cve-program · CVE-2026-93009
PublishedA 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.
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cve-program · CVE-2026-93009
PublishedDnsmasq: dnsmasq: heap out-of-bounds read in dhcpv6 option 39 fqdn decoder
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.
- Source published
- 29 Oct 2026 13:13:34 UTC
- Source modified
- 30 Oct 2026 08:05:48 UTC
- Saved here
- 30 Oct 2026 09:48:55 UTC
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- CVE Program Terms of Use
Original source record · Cite this exact observation · Complete original publisher JSON
Source: cve-program · CVE Program Terms of Use. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.
CVSS 3.1 · 4.3 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N