Bug 2494181

Summary:	CVE-2026-12490 nsd: Bypass of client certificate verification with transfer over TLS [epel-all]
Product:	[Fedora] Fedora EPEL	Reporter:	Marco Benatto <mbenatto>
Component:	nsd	Assignee:	Paul Wouters <paul.wouters>
Status:	NEW ---	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	epel10	CC:	drjohnson1, me, paul.wouters
Target Milestone:	---	Keywords:	Security, SecurityTracking
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["919c2a5e-9b29-44d4-8193-1905f61f05c2"]}
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	2491590

Description Marco Benatto 2026-06-29 13:43:53 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.

When a "provide-xfr" is given with a "tls-auth-name", a secondary requesting a transfer should provide a client certificate with that name. However, no client certificate is needed when the request comes in over TLS over the regular "tls-port" (and not the "tls-auth-port") or over over TCP over the regular port, when the other conditions of the "provide-xfr" rule match.

The transfer security restrictions for client certificates can be bypassed completely if the attacker can match the other access control conditions, and the "tls-auth-xfr-only" option is not explicitly set to "yes" (which it bydefault is not)