Vulnerability DatabaseCVE-2026-123596
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CVE-2026-123596
Published:November 08, 2026
Updated:November 09, 2026
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.
Affected Packages
https://github.com/hickory-dns/hickory-dns.git (GITHUB):
Affected version(s) >=0.5.0 <v0.26.2 || =0.6.0 <v0.26.2 || >=0.7.0 <v0.26.2 || >=0.8.0 <v0.26.2 || >=0.9.0 <v0.26.2 || >=0.10.0 <v0.26.2 || =0.11.0 <v0.26.2 || =c0.12.0 <v0.26.2 || =r0.7.0 <v0.26.2 || >=r0.8.0 <v0.26.2 || >=r0.9.0 <v0.26.2 || >=r0.10.0 <v0.26.2 || >=r0.11 <v0.26.2 || =r0.12_cs0.17 <v0.26.2 || =v0.13.0 <v0.26.2 || =v0.14.0 <v0.26.2 || =cs0.15.0 <v0.26.2 || >=cs0.16 <v0.26.2 || >=0.18.0.alpha.2 <v0.26.2 || >=0.19.0 <v0.26.2 || =v0.19.7 <v0.26.2 || >=v0.20.0-alpha.1 <v0.26.2 || >=v0.21.0-alpha.1 <v0.26.2 || >=v0.22.0 <v0.26.2 || >=v0.23.0-alpha.1 <v0.26.2 || >=v0.24.0 <v0.26.2 || >=v0.25.0-alpha.1 <v0.26.2 || >=v0.26.0-alpha.1 <v0.26.2
Fix Suggestion:
Update to version v0.26.2
hickory-net (RUST):
Affected version(s) >=0.26.0-beta.1 <0.26.2
Fix Suggestion:
Update to version 0.26.2
hickory-proto (RUST):
Affected version(s) =0.26.0-alpha.1 <0.26.2 || >=0.24.0 <0.26.2 || >=0.25.0-alpha.1 <0.26.2
Fix Suggestion:
Update to version 0.26.2
Related Resources (4)
https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/123xxx/CVE-2026-123596.json
https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-3r6v-f3jh-vvqm
https://www.vulncheck.com/advisories/hickory-dns-through-0.26.0-alpha.1-dnssec-validation-bypass-via-ancestor-delegation-nsec
https://nvd.nist.gov/vuln/detail/CVE-2026-123596
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CVSS v4
Base Score:
8.7
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
LOW
User Interaction
NONE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
8.8
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Weakness Type (CWE)
Insufficient Verification of Data Authenticity
CWE-345
EPSS
Base Score:
0.18