rustls webpki up to 0.103.11/0.104.0-alpha.5 certificate validation

Summaryinfo

A vulnerability has been found in rustls webpki up to 0.103.11/0.104.0-alpha.5 and classified as problematic. This vulnerability affects unknown code. Performing a manipulation results in certificate validation. This vulnerability is reported as CVE-2026-93600. The attack is possible to be carried out remotely. No exploit exists. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as problematic, was found in rustls webpki up to 0.103.11/0.104.0-alpha.5. This affects an unknown part. The manipulation with an unknown input leads to a certificate validation vulnerability. CWE is classifying the issue as CWE-295. The product does not validate, or incorrectly validates, a certificate. This is going to have an impact on integrity. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-93600 since 09/18/2026. The exploitability is told to be difficult. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1587.003 according to MITRE ATT&CK.

Upgrading to version 0.103.12 or 0.104.0-alpha.6 eliminates this vulnerability.

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Productinfo

Vendor

• rustls

Name

• webpki

Version

• 0.103.0
• 0.103.1
• 0.103.2
• 0.103.3
• 0.103.4
• 0.103.5
• 0.103.6
• 0.103.7
• 0.103.8
• 0.103.9
• 0.103.10
• 0.103.11
• 0.104.0-alpha.0
• 0.104.0-alpha.1
• 0.104.0-alpha.2
• 0.104.0-alpha.3
• 0.104.0-alpha.4
• 0.104.0-alpha.5

Website

• Product: https://github.com/rustls/webpki/

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