CVE-2026-97206
HIGH 7.5NLnet 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.
Severe if exploited (CVSS 7.5), but no known exploitation and low modeled probability. Patch on a normal cadence.
Exploitation likelihood
0.3%chance of exploitation in 30 days · 26th percentile
Impact if exploited
7.5CVSS 3.1 · HIGH
- ConfidentialityNone
- IntegrityNone
- AvailabilityHigh
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ✓Privileges: No account or privileges required
- ✓User interaction: No user interaction needed
- ✓Complexity: No special conditions — reliably repeatable
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept
No public PoC is currently catalogued.
Search for new PoCs
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Data snapshot:
Weakness (CWE)
- CWE-416: : Use After Free
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References and research data (JSON)
Unverified PoC candidates
Catalogue matches for further research. These repositories have not been validated as working exploits.
1 candidate
- https://github.com/suominen/CVE-2026-97206PoC-in-GitHub · CVE-2026-97206
PoC-in-GitHub · CVE-2026-97206 · Updated 2026-10-24T17:50:19Z
All CVSS metrics
- HIGH 7.5 v3.1 · CNA Primary
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - HIGH 7.5 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
Advisories
- https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-97206.txt CVE record · NLnet Labs · Updated 2026-10-21T08:57:41.106Z
NVD · CVE-2026-97206 · Updated 2026-10-22T15:22:40.700 - https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-107154 EUVD · EUVD-2026-107154