CVE-2026-81563

A BIND resolver encountering an SVCB/HTTPS AliasMode record referencing 14 or more SVCB/HTTPS ServiceMode records may fail to properly deallocate internal resources. If this happens repeatedly, resource exhaustion will eventually prevent the resolver from performing new recursive lookups. This issue affects BIND 9 versions 9.18.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.18.11-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1.

CVSS 3.1

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

EPSS

0.6% chance of exploitation in the next 30 days; higher than 46% of CVEs (scores of 2026-10-26)

CWE

CWE-401

Published

2026-09-16

Modified

2026-10-26

Record from

the NVD, synced 2026-10-26

References

• https://downloads.isc.org/isc/bind9/9.20.29
• https://downloads.isc.org/isc/bind9/9.21.26
• https://kb.isc.org/docs/cve-2026-81563

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