CVE-2026-123586 PUBLISHED

Hickory DNS 0.25.0-alpha.3 through 0.25.2 Query Amplification via Cyclic Referrals

Assigner: VulnCheck
Reserved: 06.11.2026 Published: 08.11.2026 Updated: 08.11.2026

Hickory DNS 0.25.0-alpha.3 through 0.25.2 contains a query amplification vulnerability in its recursive resolver, which mishandles cyclic sibling name server referrals that lack glue records. Attackers controlling two zones whose name servers reference each other without glue records can make the recursor loop, sending many upstream queries, amplified further by zero-TTL NS records.

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS Score: 8.7

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	None
Attack Complexity	Low	Integrity	None	Integrity	None
Attack Requirements	None	Availability	High	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS Score: 7.5

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	None
Privileges Required	None	Integrity Impact	None
User Interaction	None	Availability Impact	High

CVSS 3.1

Product Status

Vendor	hickory-dns
Product	hickory-dns
Versions	Default: unaffected affected from 0.25.0-alpha.3 to 0.25.2 (incl.)

Vendor	hickory-dns
Product	hickory-dns
Versions	Default: unaffected affected from 0 to 0.26.2 (excl.) Version 0.26.2 is unaffected

CVE-2026-123586 PUBLISHED

Hickory DNS 0.25.0-alpha.3 through 0.25.2 Query Amplification via Cyclic Referrals

Metrics

Product Status

Credits

References

Problem Types