CVE-2026-123578 Hickory DNS 0.26.0 before 0.26.2 Response Validation Bypass via QDCOUNT=0
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-123578?
CVE-2026-123578 is a medium-severity vulnerability in hickory-dns, published on 8 Nov 2026.
Official description
Hickory DNS hickory-net 0.26.0 before 0.26.2 and hickory-proto 0.25.0 through 0.25.2 skip the check that a UDP response's question section matches the query when the response has an empty question section (QDCOUNT=0), and also skip the case-randomization check. Remote attackers able to inject spoofed UDP responses can send QDCOUNT=0 responses to bypass these checks, weakening defenses against DNS spoofing.
Weakness: CWE-290
Which versions are affected by CVE-2026-123578?
How do I fix CVE-2026-123578?
Upgrade to a fixed version.
Is CVE-2026-123578 being exploited?
There is no known exploitation of CVE-2026-123578 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-123578, GHSA-3w89-7rx5-hpwx, GHSA-j6hp-65pf-mqr7, UBUNTU-CVE-2026-123578.