What’s Vulnerable › Vulnerabilities
CVE-2026-97206: DNS-over-QUIC (DoQ) path-migration can lead to use-after-free on multi-threaded deployments.
- Severity: high (CVSS 7.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.3% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-10-21 · updated 2026-10-29
- Weakness: CWE-416
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.
Affected products
- NLnet Labs Unbound: from 1.22.0 before 1.26.2 — fixed in 1.26.2
How to fix
Upgrade to a fixed version: NLnet Labs Unbound 1.26.2. Check the vendor advisory for mitigations.
References
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