# CVE-2026-123589: hickory-dns DoQ server request read timeout bypass

Source: https://junglewise.ai/threats/cve-2026-123589-the-dns-over-quic-doq-server-in-hickory-server-hickory-dns  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-08. Updated: 2026-11-08  
License: CC BY 4.0 with a link back

CVE-2026-123589 · Severity: medium · CVSS 5.3 · Published 2026-11-08

hickory-dns is a DNS server library that supports DNS-over-QUIC (DoQ), a protocol for secure DNS queries. The server fails to enforce timeouts when reading incoming DNS requests over QUIC, allowing an attacker to open a connection and hold it open indefinitely without sending a complete message. This causes the server to consume resources exhaustively, resulting in a denial of service that prevents legitimate DNS queries from being answered.

Vendors: [Hickory-Dns](https://junglewise.ai/threats/vendors/hickory-dns).

## Quick answers

**Is CVE-2026-123589 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-123589 being exploited in the wild.

**How severe is CVE-2026-123589?** Medium severity, with a CVSS score of 5.3, published 8 November 2026.

**Which products and versions are affected?** Hickory-Dns Hickory-Server <0.26.2.

**Is there a fix for CVE-2026-123589?** Yes: fixed in 0.26.2. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-123589 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-123589?** Check whether you run Hickory-Dns Hickory-Server at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 0.26.2

## Technical details

The DoQ server implementation in hickory-dns before 0.26.2 does not apply any timeout constraint to the stream read operation for incoming request messages, bypassing the application's configured timeouts. A remote unauthenticated client can exploit this via the network by opening a QUIC connection, starting a request stream, and holding it open indefinitely. This causes server resource exhaustion and denial of service; a fix is available in version 0.26.2 and later.

## Affected products

- hickory-dns hickory-server <0.26.2

## Timeline

- 2026-09-03: disclosed
- 2026-11-08: advisory

## References

- [https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-g8wg-4mwh-fjfv](https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-g8wg-4mwh-fjfv)
- [https://www.vulncheck.com/advisories/hickory-dns-before-0.26.2-denial-of-service-via-missing-dns-over-quic-request-read-timeout](https://www.vulncheck.com/advisories/hickory-dns-before-0.26.2-denial-of-service-via-missing-dns-over-quic-request-read-timeout)

## Related threats

- [Hickory DNS IPv4-mapped IPv6 canonicalization bypass](https://junglewise.ai/threats/cve-2026-123603-hickory-proto-and-hickory-resolver-0-26-0-before-0-26-2-hickory)