VU#410595: Google BoringSSL Name Constraints Bypass in SAN Validation Logic

Summary

Overview Five Name Constraints findings in BoringSSL (VU#410595.8–.12) describe cases where certificate names may not be constrained as intended. Records .8, .9, .10 and .12 concern the legacy crypto/x509 path; .11 concerns the newer pki path. Two have been fixed, one is accepted, one is disputed, and one was declined. Description Name Constraints limit the names a subordinate certificate authority may issue. The reports concern how BoringSSL applies those limits to certain SAN (Subject Alternative Name) forms. The records do not share one status, and they do not all affect the same validation path. VU#410595.8 ( Fixed 2026-03-04 ): A wildcard DNS name may not be treated as covering a specifically excluded host. VU#410595.9 ( Accepted ): A URI with a colon before @ may cause the wrong host to be used when matching URI constraints...

Why it matters

CERT/CC notes often cover coordinated disclosures, multi-vendor exposure, infrastructure risk, or cases where remediation guidance is still developing.

Operator check

Review the CERT/CC Vulnerability Note and compare the affected vendor and product list against your inventory. Apply vendor fixes or compensating controls for Validation Logic where available.

Sources