Integer Underflow in Hickory DNS Affects Remote Systems
CVE-2026-123571

8.7HIGH

Key Information:

Vendor

Hickory-dns

Status
Hickory-dns
Vendor
CVE Published:
8 November 2026

What is CVE-2026-123571?

Hickory DNS versions 0.26.0 through 0.26.1 contain an integer underflow vulnerability within the TSIG RDATA decoding process. This flaw allows remote attackers to exploit malformed TSIG records, potentially triggering a panic and causing denial of service in affected builds that have overflow checks enabled. Effective mitigation is crucial for maintaining the stability and security of DNS services relying on Hickory DNS.

Affected Version(s)

hickory-dns 0.26.0 < 0.26.2

hickory-dns 0.26.2

References

https://github.com/hickory-dns/hickory-dns/security/advis...
vendor-advisory
https://www.vulncheck.com/advisories/hickory-dns-from-0.2...
third-party-advisory

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

JasonPap
.