Bug 2568804 (CVE-2026-123578)

Summary: CVE-2026-123578 hickory-net: hickory-proto: Hickory DNS: DNS spoofing defense bypass via empty question section
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: dbosanac, jcantril, jlanda, jreimann, kshier, mdessi, mrizzi, pcattana, rbobbitt, rhel-process-autobot, rojacob, simaishi, stcannon, watson-tool-maintainers, yguenane
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in Hickory DNS. When processing User Datagram Protocol (UDP) responses with an empty question section, the resolver skips validation checks that verify the response matches the original query and bypasses case-randomization protections. A remote attacker capable of injecting forged network packets can exploit this flaw to bypass verification mechanisms and facilitate Domain Name System (DNS) spoofing attacks.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description OSIDB Bzimport 2026-11-08 02:06:16 UTC
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.