Bug 2548164

Summary:	CVE-2026-93600 arapuca: rustls-webpki: URI Name Constraint Bypass via X.509 Certificate Misissue [fedora-all]
Product:	[Fedora] Fedora	Reporter:	Ganesh <gnaik>
Component:	arapuca	Assignee:	Sergio Correia <scorreia>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	rawhide	CC:	scorreia
Target Milestone:	---	Keywords:	Security, SecurityTracking
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["ab1878dc-6ee9-4241-bf74-8bb913187643"]}
Fixed In Version:		Doc Type:	---
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2026-10-13 21:20:18 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	2538296

Description Ganesh 2026-10-08 18:49:06 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.

rustls-webpki (rustls/webpki) versions 0.101.0 through 0.103.11 and 0.104.0-alpha releases before 0.104.0-alpha.6 ignore X.509 name constraints that apply to URI names, causing such constraints to be accepted rather than enforced. Because name constraints are restrictions on otherwise properly issued certificates, the flaw is only reachable after successful signature verification and requires a misissued certificate to exploit; the library also provides no API for asserting URI names, and URI name constraints are otherwise unimplemented. Versions 0.103.12 and 0.104.0-alpha.6 reject URI name constraints unconditionally.

Comment 1 Sergio Correia 2026-10-13 21:20:18 UTC

The rustls-webpki crate is a transitive dependency pulled in by reqwest → rustls, both gated behind the optional microvm Cargo feature. This feature is not enabled in the Fedora build; the spec uses %cargo_build with no --features microvm. The vendored source includes stubs for these deps but they are not compiled or linked.

Even if the microvm feature were enabled, the URI Name Constraint bypass requires a misissued X.509 certificate with URI SANs from a trusted CA. arapuca's only use of TLS is fetching VM images from trusted registries.

Closing as NOTABUG, as it is not affected.