Description
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.
Published: 2026-09-18
Score: 2.1 Low
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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History

Fri, 18 Sep 2026 13:30:00 +0000

Type Values Removed Values Added
Description 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.
Title rustls webpki 0.101.0 before 0.103.12 Name Constraint Bypass
Weaknesses CWE-295
References
Metrics cvssV3_1

{'score': 2.2, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:N'}

cvssV4_0

{'score': 2.1, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N'}

Subscriptions

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-09-18T13:20:11.571Z

Reserved: 2026-09-18T11:00:32.756Z

Link: CVE-2026-93601

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-18T14:19:11.707

Modified: 2026-09-18T14:19:11.707

Link: CVE-2026-93601

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses
  • CWE-295

    Improper Certificate Validation