Hickory DNS 0.24.0 before 0.26.2 Denial of Service via Zone File Parser
Affects hickory-proto 0.24.0 through 0.26.1 when a zone file contains a single token 4096 bytes or longer. Fixed in Hickory DNS 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? →
- 0.34% · 28th 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? →
- 26/100 · 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 zone file parser in the hickory-proto crate of Hickory DNS 0.24.0 before 0.26.2 panics when a single token in a zone file is 4096 bytes or longer. Attackers who can supply untrusted zone files to an application using the parser can trigger the panic to cause a denial of service.
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
- Severity8.7/10CVSS 8.7
- No patch0/5No signal
What would change the score
- Would score about 71 if added to CISA KEV
- Would score about 66 if CISA's SSVC rates exploitation active
- Would score about 31 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
From 0.24.0 · 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-2026-123574
Is CVE-2026-123574 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 single token in a zone file that is 4096 bytes or longer makes the parser panic. A panic makes the application that parses untrusted zone files unavailable, which is a denial of service.Source: github.com, vulncheck.com
Which versions are affected by CVE-2026-123574?
hickory-dns: from 0.24.0 before 0.26.2.Source: cve.now feed data
Am I affected, and how do I check?
The hickory-proto crate versions 0.24.0 through 0.26.1 are affected, and only when a zone file has a single token of 4096 bytes or longer. A reader can check the hickory-proto version in the Cargo.lock file or the dependency tree of the application.Source: github.com, vulncheck.com
How do I fix CVE-2026-123574?
Upgrade to Hickory DNS 0.26.2, the fixed version.Source: github.com, vulncheck.com