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Hickory DNS missing request read timeout enables denial of service

Priority LOW 30Published · Updated

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

EPSS 0.00333 26th percentileScored 2026-11-08
Fix Fixed hickory-dns (hickory-dns): 0.26.2

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
hickory-dnshickory-dnsbefore 0.26.20.26.2Patch availableCNA
  • 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

  1. 2026-11-08 Threatist record created from CVE-2026-123589
  2. 2026-11-08 Alias added: GHSA-hpqr-cvqv-p4qm
  3. 2026-11-09 Priority changed: MEDIUM → LOW

References

  • 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
See all 40 →

Sources