Bug 2559983

Summary:	CVE-2026-93601 rustup: rustls-webpki: Name Constraint Bypass in wildcard certificate validation [fedora-all]
Product:	[Fedora] Fedora	Reporter:	Ronit Dey <rdey>
Component:	rustup	Assignee:	Rust SIG <rust-sig>
Status:	ON_QA ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	rawhide	CC:	decathorpe, rust-sig, suraj.ghimire7
Target Milestone:	---	Keywords:	Security, SecurityTracking
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["94568926-7455-4c8f-8f71-63ce67f08abb"]}
Fixed In Version:		Doc Type:	---
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:		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:	2538656

Description Ronit Dey 2026-10-23 15:55:32 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 (the Rust webpki fork used by rustls) versions >= 0.101.0 and prior to 0.103.12 and 0.104.0-alpha.6 incorrectly accepted permitted-subtree DNS name constraints for certificates asserting a wildcard name. For example, a name constraint of accept.example.com was treated as satisfied by a certificate for *.example.com, which could feasibly assert reject.example.com — a name outside the permitted subtree. Because name constraints are restrictions applied to otherwise properly issued certificates, the issue is only reachable after signature verification succeeds and requires a misissued wildcard certificate to exploit.

Comment 1 Fedora Update System 2026-11-06 15:53:24 UTC

FEDORA-2026-0628ac17ea (rustup-1.29.0-10.fc45) has been submitted as an update to Fedora 45.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-0628ac17ea

Comment 2 Fedora Update System 2026-11-06 15:53:25 UTC

FEDORA-2026-3e53e965a2 (rustup-1.29.0-10.fc44) has been submitted as an update to Fedora 44.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-3e53e965a2

Comment 3 Fedora Update System 2026-11-06 15:53:26 UTC

FEDORA-2026-565fd36f29 (rustup-1.29.0-10.fc43) has been submitted as an update to Fedora 43.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-565fd36f29

Comment 4 Fedora Update System 2026-11-07 02:32:08 UTC

FEDORA-2026-3e53e965a2 has been pushed to the Fedora 44 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-3e53e965a2`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-3e53e965a2

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 5 Fedora Update System 2026-11-07 02:53:30 UTC

FEDORA-2026-0628ac17ea has been pushed to the Fedora 45 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-0628ac17ea`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-0628ac17ea

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 6 Fedora Update System 2026-11-07 03:14:04 UTC

FEDORA-2026-565fd36f29 has been pushed to the Fedora 43 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-565fd36f29`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-565fd36f29

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.