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Fencer Vulns
high 7.5

CVE-2026-97206 json

DNS-over-QUIC (DoQ) path-migration can lead to use-after-free on multi-threaded deployments.

published 2026-10-21 19 d ago modified 2026-10-29 10 d ago also EUVD-2026-107154

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 26%
public exploits
0
none known

Summary

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.

Patch / fix

  • NLnet Labs Unbound 1.26.2
  • unbound Debian 13 1.26.2-0+deb13u1
  • unbound Debian 14 1.26.2-1

debian advisories DEBIAN-CVE-2026-97206

  • unbound openSUSE Tumbleweed 1.26.2-1.1

opensuse advisories openSUSE-SU-2026:12257-1

  • unbound Azure Linux 3.0 1.26.2-1

azure linux advisories AZL-109824

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
10 d ago

Exploit prediction

0.33% chance of exploitation in the next 30 days, higher than 26% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • NLnet Labs Unbound

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.