hickory-dns from 0.20.1 before 0.26.2 Panic in SVCB/HTTPS Zone File Parser
Affects hickory-dns 0.20.1 through 0.26.1 where untrusted zone files with SVCB or HTTPS records are parsed. 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? →
- 0.34% · 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
hickory-dns from 0.20.1 before 0.26.2 contains a denial of service vulnerability in the hickory-proto SVCB and HTTPS record presentation format parser. Attackers can supply untrusted zone files where only a single or double quote replaces a service parameter value, triggering a panic that crashes the parsing process.
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 0.20.1 · 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-2026-123573
Is CVE-2026-123573 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 or double quote replacing a service parameter value in a SVCB or HTTPS zone file record triggers a panic. The panic crashes the zone file parsing process, causing a denial of service.Source: github.com, vulncheck.com
Which versions are affected by CVE-2026-123573?
hickory-dns: from 0.20.1 before 0.26.2.Source: cve.now feed data
Am I affected, and how do I check?
hickory-proto versions v0.20.1 through v0.26.1 are affected, which corresponds to hickory-dns from 0.20.1 before 0.26.2. The concern is systems that parse untrusted zone files containing SVCB or HTTPS records. Check the hickory-proto or hickory-dns version in the dependency tree to see whether it falls in that range.Source: github.com, vulncheck.com
How do I fix CVE-2026-123573?
Upgrade to hickory-dns 0.26.2 or later, which contains the fix.Source: github.com, vulncheck.com