Hickory DNS Recursor Ghost Domain Attack via Child-Side NS RRset Caching
Affects hickory-dns up to 0.26.0-alpha.1, and 0.26.0-beta.1 before 0.26.2 with the recursor feature enabled. Fixed in 0.26.2.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 0.26.2
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 0.26.2.
- Last modified
- FIRST's estimate of the chance attackers exploit it in the next 30 days, updated daily.What do these mean? →
- 0.27% · 19th percentile
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 25/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
The Hickory DNS recursor in all versions of hickory-recursor and in hickory-resolver 0.26.0-beta.1 before 0.26.2 (recursor feature) is vulnerable to ghost domain names attacks because it reuses child-side apex NS RRsets cached from zone NS queries for iterative resolution. By repeatedly querying a zone's NS records, an attacker keeps the stale RRset cached indefinitely, letting name servers whose delegation the parent revoked keep answering for the zone.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure17/25No login or user action needed, reachable over the network without a login · Unknown: Advisories don't say whether default setups are affected
- Reach?/20Unknown. No tracked technology or package matched
- Severity8.2/10CVSS 8.2
- No patch0/5No signal
What would change the score
- Would score about 70 if added to CISA KEV
- Would score about 65 if CISA's SSVC rates exploitation active
- Would score about 30 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 0.26.2.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- hickory-dns hickory-dns
through 0.26.0-alpha.1
- hickory-dns hickory-dns
From 0.26.0-beta.1 · fixed in 0.26.2
Evidence 2
- Advisory
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-123602
Is CVE-2026-123602 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
A name server that a parent zone has revoked can keep answering for the zone. The recursor keeps reusing the zone's apex NS records that it cached from the zone's own name servers, so the stale delegation stays in use while it remains in cache.Source: github.com, vulncheck.com
Which versions are affected by CVE-2026-123602?
hickory-dns: through 0.26.0-alpha.1. hickory-dns: from 0.26.0-beta.1 before 0.26.2.Source: cve.now feed data
Am I affected, and how do I check?
The product list covers hickory-dns up to 0.26.0-alpha.1 and hickory-resolver 0.26.0-beta.1 before 0.26.2 with the recursor feature enabled. The hickory-recursor crate is listed as affected in all versions. To check, look at the hickory-resolver version in Cargo.lock and whether the recursor feature is enabled in Cargo.toml.Source: github.com, vulncheck.com
How do I fix CVE-2026-123602?
Upgrade hickory-dns to 0.26.2 or later. The facts list no workaround.Source: github.com, vulncheck.com