Hickory DNS missing request read timeout enables denial of service
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · Low
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA.
Summary
The DNS-over-QUIC server in hickory-server (hickory-dns) before 0.26.2 applies no timeout when reading a request message from a QUIC stream, so configured timeouts are bypassed. A remote unauthenticated client can open a connection and a request stream and hold it open indefinitely, consuming server resources and causing a denial of service.
Written with Claude Haiku 5.5 from the sources below · 2026-11-08
Description from the CNA
The DNS-over-QUIC (DoQ) server in hickory-server (hickory-dns) before 0.26.2 does not apply any timeout when reading a request message from a QUIC stream, bypassing all configured timeouts. A remote unauthenticated client can open a connection and a request stream and hold it open indefinitely, consuming server resources and causing a denial of service.
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 | before 0.26.2 | 0.26.2 | Patch available | CNA |
- hickory-dns Vendorhickory-dns Affected before 0.26.2 Fixed in 0.26.2 Patch available CNA
Remediation
Upgrade hickory-dns to version 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 LOW 36 LOW
Other records, highest priority first
- TI-2026-86748 Resource exhaustion in hickory-dns recursor via glueless NS referralsPriority LOW 38
- TI-2026-86746 Unbounded retry loop in Hickory DNS resolver enables resource exhaustionPriority LOW 38
- TI-2026-86730 Denial of service in Hickory DNS recursive resolver via empty poolPriority LOW 38
Timeline
- 2026-11-08 Threatist record created from CVE-2026-123589
- 2026-11-08 Alias added: GHSA-hpqr-cvqv-p4qm
- 2026-11-09 Priority changed: MEDIUM → LOW
References
More hickory-dns vulnerabilities
- TI-2025-18857 DNSSEC validation may accept broken authentication chains CVSS 4.0MEDIUM 5.7
- TI-2026-63089 hickory-resolver before 0.26.2 DNSSEC Validation Bypass CVSS 4.0HIGH 8.7
- 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-2026-86746 Unbounded retry loop in Hickory DNS resolver enables resource exhaustion CVSS 4.0HIGH 8.7
Sources
- CVE-2026-123589 · CVE Program
- CVE-2026-123589 · NVD
- FIRST EPSS
- GHSA-hpqr-cvqv-p4qm · GitHub Advisory Database · CC BY 4.0
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