CVE-2019-16866

Unbound before 1.9.4 accesses uninitialized memory, which allows remote attackers to trigger a crash via a crafted NOTIFY query. The source IP address of the query must match an access-control rule.

CVSS 3.1

7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

3.5% chance of exploitation in the next 30 days; higher than 89% of CVEs (scores of 2026-10-25)

CWEs

CWE-755, CWE-908

Published

2019-10-03

Modified

2026-10-08

Record from

the NVD, synced 2026-10-19

Affected

• canonical:ubuntu_linux
• nlnetlabs:unbound

References

• https://github.com/NLnetLabs/unbound/blob/release-1.9.4/doc/Changelog
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/E65NCWZZB2D75ZIYWPXKMVGSGNYW4JMC/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MLRHE7TQFAOV4MB2ELTOGESZYUL65NUJ/
• https://nlnetlabs.nl/downloads/unbound/CVE-2019-16866.txt
• https://seclists.org/bugtraq/2019/Oct/23

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