Bug 2535876

Summary:	CVE-2026-81563 bind: BIND resolver: Denial of Service due to resource exhaustion in SVCB/HTTPS AliasMode processing [fedora-all]
Product:	[Fedora] Fedora	Reporter:	Vladimir Vasilev <vvasilev>
Component:	bind	Assignee:	Petr Menšík <pemensik>
Status:	NEW ---	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	high	Docs Contact:
Priority:	high
Version:	rawhide	CC:	anon.amish, dns-sig, mruprich, pemensik, zdohnal
Target Milestone:	---	Keywords:	Security, SecurityTracking
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["eb709019-2a4e-45f2-af15-8a14a71c13b2"]}
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	2535461

Description Vladimir Vasilev 2026-09-17 08:51:50 UTC

Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

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.