# CVE-2026-123580: Hickory DNS DNSSEC nonexistence proof forgery in NSEC3 verification

Source: https://junglewise.ai/threats/cve-2026-123580-hickory-dns-hickory-net-0-26-0-beta-1-before-0-26-2-and-hickory  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-08. Updated: 2026-11-08  
License: CC BY 4.0 with a link back

CVE-2026-123580 · Severity: high · CVSS 7.5 · Published 2026-11-08

Hickory DNS is a DNS resolver library used to look up domain names on the internet. A flaw in DNSSEC security checks allows attackers to forge proof that a domain doesn't exist, potentially redirecting users to malicious websites or enabling DNS spoofing attacks. An attacker on the network can exploit this without any special privileges.

Technologies: [Hickory-Dns Hickory-Net](https://junglewise.ai/threats/technologies/hickory-dns-hickory-net), [Hickory-Dns Hickory-Proto](https://junglewise.ai/threats/technologies/hickory-dns-hickory-proto). Vendors: [Hickory-Dns](https://junglewise.ai/threats/vendors/hickory-dns).

## Quick answers

**Is CVE-2026-123580 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-123580 being exploited in the wild.

**How severe is CVE-2026-123580?** High severity, with a CVSS score of 7.5, published 8 November 2026.

**Which products and versions are affected?** Hickory-Dns Hickory-Net 0.26.0-beta.1 through 0.26.1; Hickory-Dns Hickory-Proto through 0.26.0-alpha.1.

**Is there a fix for CVE-2026-123580?** Yes: fixed in hickory-net 0.26.2. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-123580 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-123580?** Check whether you run Hickory-Dns Hickory-Net or Hickory-Dns Hickory-Proto at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in hickory-net 0.26.2

## Technical details

The vulnerability exists in DNSSEC NSEC3 record validation: the code compares only the hashed label of an NSEC3 record without verifying that the record belongs to the queried zone, allowing attackers to supply NSEC3 records from another zone with a matching hash to forge nonexistence proofs. This is an authentication bypass vulnerability requiring only network access and no user interaction. An attacker can manipulate DNSSEC responses to make valid domains appear nonexistent.

## Affected products

- hickory-dns hickory-net 0.26.0-beta.1 through 0.26.1
- hickory-dns hickory-proto through 0.26.0-alpha.1

## Timeline

- 2026-09-03: disclosed: GitHub security advisory published
- 2026-11-08: advisory: CVE-2026-123580 published

## References

- [https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-p2jv-r3m3-7wf4](https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-p2jv-r3m3-7wf4)
- [https://www.vulncheck.com/advisories/hickory-dns-0.26.0-beta.1-before-0.26.2-dnssec-nonexistence-proof-forgery-via-nsec3](https://www.vulncheck.com/advisories/hickory-dns-0.26.0-beta.1-before-0.26.2-dnssec-nonexistence-proof-forgery-via-nsec3)

## Related threats

- [Hickory DNS hickory-proto denial of service in BinEncoder](https://junglewise.ai/threats/cve-2026-123608-hickory-dns-hickory-proto-from-0-3-1-before-0-26-1-contains-a)
- [Hickory DNS NSEC3 closest-encloser proof unbounded loop](https://junglewise.ai/threats/cve-2026-123607-hickory-dns-hickory-proto-0-25-0-alpha-3-through-0-25-2-and)
- [Hickory DNS DNSSEC validation bypass via RRSIG Signer's Name](https://junglewise.ai/threats/cve-2026-123605-hickory-dns-hickory-proto-0-1-through-0-25-0-alpha-3-and-hickory)
- [Hickory DNS IPv4-mapped IPv6 canonicalization bypass](https://junglewise.ai/threats/cve-2026-123603-hickory-proto-and-hickory-resolver-0-26-0-before-0-26-2-hickory)
- [Hickory DNS NSEC3 comparison operator inversion](https://junglewise.ai/threats/cve-2026-123601-hickory-dns-hickory-proto-0-25-0-through-0-26-0-alpha-1-and)