CVE-2026-81563

SVCB AliasMode additional-data error leaks qpcache references

Published: Sep 16, 2026Updated: Sep 17, 2026 Sources: CVE List NVDCWE-401

7.5HIGH

Description

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.

No summary for this CVE yet.

CVSS Vector Breakdown

Exploitability

AV:NAttack Vector

Network

AC:LAttack Complexity

Low

PR:NPrivileges Required

None

UI:NUser Interaction

None

Scope

S:UScope

Unchanged

Impact

C:NConfidentiality

None

I:NIntegrity

None

A:HAvailability

High

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Weaknesses

CWE-401

Affected Products

ISC

commercial·USaka internet systems consortium

BIND 9

Networking Infrastructure

Exploitability

0 exploit sources identified

Exploit details including PoC links, Metasploit modules, and scanner templates are available after registration.

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Official Patch Available

Workaround Available

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References

https://kb.isc.org/docs/cve-2026-81563

kb.isc.org

https://downloads.isc.org/isc/bind9/9.20.29

downloads.isc.org

https://downloads.isc.org/isc/bind9/9.21.26

downloads.isc.org

News mentions

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