CVE-2026-93600

rustls webpki Name Constraints URI Validation Bypass

LOW
2.2
CVSS Score
Published: September 18, 2026 at 01:20 PM UTC
Updated: September 22, 2026 at 08:41 PM UTC
1 product affected across 1 vendorWebpki

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Severity
LOW2.2
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

0.101.0 ≤ v < 0.103.120.104.0-alpha.1 ≤ v < 0.104.0-alpha.60.101.00.104.0-alpha.1
Affected range stops below 0.103.12, so it looks safe — our inference, not a vendor statement
Affected range stops below 0.104.0-alpha.6, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

2.2LOWVulnCheck
Attack Vector
NETWORK
Complexity
HIGH
Privileges
HIGH
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-295

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