pyca/cryptography (Product): news timeline & CVEs

VU#948176: Multiple TLS Libraries can Bypass Delegation Enforcement

CERT/CC says TLS libraries inconsistently enforce Name Constraints, with three assigned CVEs already fixed.

CERT/CC VU#948176 documents library-specific disagreements in enforcing X.509 Name Constraints across DNS, IP, URI, and Common Name handling. Assigned fixes include GnuTLS CVE-2026-3833 in 3.8.13, pyca/cryptography CVE-2026-34073 in 46.0.6, and wolfSSL CVE-2026-3547 in 5.9.0; OpenSSL merged PR #30319 for one URI case. Reports involving Go, Apple Security.framework, Mozilla NSS, LibreSSL, AWS-LC, s2n-tls, and Mbed TLS are fixed, in triage, disputed, or not accepted as security issues. CERT/CC does not report active exploitation and says impact depends on trusted issuance and the affected validation path.

CERT/CC Vulnerability Notesupdated Oct 14, 18:50 UTC · 2d agofirst Oct 14, 15:11 UTC · 2d agoVulnerability 4 sources CVE-2026-3833 CVE-2026-34073 CVE-2026-35472

VU#573195: Go, OpenSSL, Apple, LibreSSL, pyca, wolfSSL Name-Constraint Inconsistency in RFC 5280 Implementation

CERT/CC warns TLS libraries inconsistently enforce X.509 name constraints, with fixes for GnuTLS and pyca/cryptography.

CERT/CC VU#573195 describes inconsistent X.509 Name Constraints handling across Go crypto/x509, Apple Security.framework, OpenSSL, LibreSSL, pyca/cryptography, and wolfSSL. Differences cover DNS comparison, IPv4-mapped IPv6 addresses, URI-authority parsing, and wildcards; some are defects and others stem from gaps in RFC 5280. GnuTLS case-sensitivity issue CVE-2026-3833 was fixed in 3.8.13, and pyca/cryptography CVE-2026-34073, where constraints were not checked against the requested peer name, was fixed in 46.0.6. CERT/CC says an attacker would need a trusted signature and a relying application, and that disagreement alone does not show exploitation.

CERT/CC Vulnerability Notesupdated Oct 14, 18:50 UTC · 2d agofirst Oct 13, 18:27 UTC · 3d agoVulnerability 4 sources CVE-2026-3833 CVE-2026-34073

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VU#948176: Multiple TLS Libraries can Bypass Delegation Enforcement

VU#573195: Go, OpenSSL, Apple, LibreSSL, pyca, wolfSSL Name-Constraint Inconsistency in RFC 5280 Implementation