Bug 2568802 (CVE-2026-123597)

Summary: CVE-2026-123597 hickory-proto: hickory-net: Hickory DNS: Denial of Service via caching of transient DNSSEC lookup errors
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
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Hardware: All   
OS: Linux   
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A flaw was found in Hickory DNS. A remote attacker can cause a Denial of Service (DoS) by inducing transient lookup errors, such as server failures or timeouts, during Domain Name System Security Extensions (DNSSEC) Delegation Signer (DS) queries. The resolver improperly caches these temporary query failures as invalid validation verdicts, causing it to reject legitimate resolution requests for all names under the affected zone until the cache expires.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-11-08 02:06:16 UTC
Hickory DNS hickory-proto 0.25.0-alpha.1 through 0.26.0-alpha.1 and hickory-net before 0.26.2 contain a logic bug in DnssecDnsHandle's DS-fetch path that caches transient DS lookup errors as Bogus DNSSEC validation verdicts. An attacker who induces a SERVFAIL, REFUSED, or timeout response to a child-zone DS sub-query causes the validator to return SERVFAIL for all names under that zone until the cache entry's TTL expires.