Bug 2568760 (CVE-2026-123596) - CVE-2026-123596 hickory-proto: hickory-net: Hickory DNS: Denial of Service via improper DNSSEC NSEC record validation
Summary: CVE-2026-123596 hickory-proto: hickory-net: Hickory DNS: Denial of Service vi...
Keywords:
Status: NEW
Alias: CVE-2026-123596
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
low
low
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-11-08 02:01 UTC by OSIDB Bzimport
Modified: 2026-11-08 02:01 UTC (History)
15 users (show)

Fixed In Version:
Clone Of:
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Description OSIDB Bzimport 2026-11-08 02:01:59 UTC 
Hickory DNS hickory-proto through 0.26.0-alpha.1 and hickory-net 0.26.0-beta.1 before 0.26.2 contain a DNSSEC validation flaw in the validating recursor's NSEC handler that accepts parent-side ancestor-delegation NSEC records as proof of nonexistence for names below the zone cut. An on-path attacker, rogue parent nameserver, or attacker winning a port and TXID race can deliver one forged NXDOMAIN response built from genuinely signed parent NSEC records, causing authenticated denial of existing child-zone names cached for the negative TTL.
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