Panic in hickory-dns SVCB and HTTPS zone file parser
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA.
Summary
hickory-dns from 0.20.1 before 0.26.2 contains a denial of service flaw in the hickory-proto parser for SVCB and HTTPS record presentation format. Improper input validation (CWE-20) lets attackers supply untrusted zone files where a single or double quote replaces a service parameter value, causing a panic that crashes the parsing process. The source description does not state the privileges required beyond supplying the zone file.
Written with Claude Haiku 5.5 from the sources below · 2026-11-08
Description from the CNA
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.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| hickory-dns | hickory-dns | 0.20.1 to before 0.26.2 | 0.26.2 | Patch available | CNA |
- hickory-dns Vendorhickory-dns Affected 0.20.1 to before 0.26.2 Fixed in 0.26.2 Patch available CNA
Remediation
Upgrade hickory-dns to version 0.26.2. The sources list no fixed version for hickory-dns other than 0.26.2.
Written with Claude Haiku 5.5 from the sources below · 2026-11-08
- Fix · CNA hickory-dns (hickory-dns) Fixed in 0.26.2
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
hickory-dns 0.26.2
36 records Highest priority Priority MEDIUM 36 MEDIUM
Other records, highest priority first
- TI-2026-86729 DNSSEC nonexistence forgery in Hickory DNS via wraparound NSECPriority MEDIUM 54
- TI-2026-86748 Resource exhaustion in hickory-dns recursor via glueless NS referralsPriority MEDIUM 53
- TI-2026-86747 DNSSEC validation bypass in Hickory DNS via RRSIG signer namePriority MEDIUM 53
Timeline
- 2026-11-08 Threatist record created from CVE-2026-123573
- 2026-11-08 Alias added: GHSA-9x38-fc36-mpgq
References
More hickory-dns vulnerabilities
- TI-2025-18857 DNSSEC validation may accept broken authentication chains CVSS 4.0MEDIUM 5.7
- TI-2026-86729 DNSSEC nonexistence forgery in Hickory DNS via wraparound NSEC CVSS 4.0HIGH 8.9
- TI-2026-86750 CPU exhaustion in Hickory DNS hickory-proto via BinEncoder name compression CVSS 4.0HIGH 8.7
- TI-2026-86749 Hickory DNS NSEC3 validation loop enables denial of service CVSS 4.0HIGH 8.7
- TI-2026-86748 Resource exhaustion in hickory-dns recursor via glueless NS referrals CVSS 4.0HIGH 8.7
- TI-2026-86747 DNSSEC validation bypass in Hickory DNS via RRSIG signer name CVSS 4.0HIGH 8.7
Sources
- CVE-2026-123573 · CVE Program
- CVE-2026-123573 · NVD
- GHSA-9x38-fc36-mpgq · GitHub Advisory Database · CC BY 4.0
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