CVE-2026-93600

rustls webpki Name Constraints URI Validation Bypass

Published Sep 18, 2026 CVSS 4.0 · 2.1 Low EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Rustls
Rustls webpki
Vendors & Products Rustls
Rustls webpki
Type Values Removed Values Added
Description 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.
Title rustls webpki Name Constraints URI Validation 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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Sep 21, 2026, 8:51 PM
Reserved
Sep 18, 2026, 11:00 AM
Status
Awaiting Analysis
Published
Sep 18, 2026, 2:19 PM
Modified
Sep 22, 2026, 8:25 PM
Severity
Low
Public date
Sep 18, 2026, 1:20 PM