CVE-2026-97206 DNS-over-QUIC (DoQ) path-migration can lead to use-after-free on multi-threaded deployments.
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-97206?
CVE-2026-97206 is a high-severity vulnerability in NLnet Labs Unbound, published on 21 Oct 2026.
Official description
NLnet Labs Unbound, 1.22.0 up to and including version 1.26.1, contains a DNS-over-QUIC (DoQ) lifetime bug reachable by a remote DoQ client under multi-threaded operation. A client-triggered QUIC path migration can enter stream/connection cleanup while a mesh reply still retains a pointer to the DoQ stream. Cleanup frees the DoQ stream and when the pending mesh reply later completes it dereferences a stale pointer leading to a crash.
Weakness: CWE-416
Which versions are affected by CVE-2026-97206?
How do I fix CVE-2026-97206?
Upgrade to a fixed version.
Is CVE-2026-97206 being exploited?
There is no known exploitation of CVE-2026-97206 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as AZL-109824, DEBIAN-CVE-2026-97206, ECHO-c92f-53fb-23d0, GHSA-jc7q-6h55-rr57, UBUNTU-CVE-2026-97206.