---
id: "CVE-2026-123576"
page: "https://infrastack.ai/live/CVE-2026-123576"
kind: "vulnerability"
aliases: ["CVE-2026-123576"]
title: "Hickory DNS: incomplete DNS-over-QUIC requests exhaust server memory"
severity: "high"
cvss: 8.7
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["dns-over-quic", "dns-server", "hickory-dns", "package", "rust"]
not_affected_if: ["dns-over-quic-disabled", "other-dns-software"]
published_at: "2026-11-08T02:16:50+00:00"
first_seen_at: "2026-11-08T02:21:12+00:00"
updated_at: "2026-11-08T02:22:53+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-123576", "first_seen_at": "2026-11-08T02:21:12+00:00"}]
exploit_sources: []
---

# Hickory DNS: incomplete DNS-over-QUIC requests exhaust server memory

Link for people: https://infrastack.ai/live/CVE-2026-123576 (this .md is for agents)

Hickory DNS, a DNS server library and server, lets a remote attacker open many DNS-over-QUIC connections and send only large length prefixes. The server pre-allocates buffers for those requests that never time out, so memory runs out.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the Hickory DNS version in your `Cargo.lock` or dependency tree (for example `cargo tree -i hickory-proto` or `cargo tree -i hickory-server`).
- Look for DNS-over-QUIC listeners enabled on port 853 in your server configuration.

## Fix

- Hickory DNS: move to a version above `0.26.1` (the affected range is `0.24.0` through `0.26.1`; the exact fixed version is unknown from these sources).

## Timeline

- 2026-11-08T02:21:12+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-123576

## Documents

- [advisory] Vendor advisory: github.com https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-2f4m-fq7w-mrgx
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/hickory-dns-0.24.0-through-0.26.1-memory-exhaustion-via-dns-over-quic-requests

## From the sources

Hickory DNS 0.24.0 through 0.26.1 contains a memory exhaustion vulnerability that allows remote attackers to consume server resources by sending incomplete DNS-over-QUIC request bodies. Attackers can open many connections and send only large length prefixes, causing pre-allocated buffers to persist without timeout and exhausting server memory.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_