Panic denial of service in Hickory-dns SVCB/HTTPS zone 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 SVCB and HTTPS record presentation format parser. The parser fails to validate malformed alpn values (CWE-1286), so it panics. An unauthenticated remote attacker can supply untrusted zone files with malformed alpn parameters to crash the parsing process.
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, which panics on malformed alpn values. Attackers can supply untrusted zone files with unbalanced quotes, consecutive commas, or invalid escapes in alpn parameters to crash parsing processes.
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 or later.
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-2026-123572
- 2026-11-08 Alias added: GHSA-j8hx-pr94-c5mv
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-2026-123572 · CVE Program
- CVE-2026-123572 · NVD
- GHSA-j8hx-pr94-c5mv · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences