VU#948176: Multiple TLS Libraries can Bypass Delegation Enforcement
CERT/CC says TLS libraries inconsistently enforce Name Constraints, with three assigned CVEs already fixed.
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CVE-2026-3833
- CVSS 3.1
- 7.4 high
- EPSS
- <1%p47
- Published
- ·
- Modified
Description · NVD
A flaw was found in gnutls. This vulnerability occurs because gnutls performs case-sensitive comparisons of `nameConstraints` labels, specifically for `dNSName` (DNS) or `rfc822Name` (email) constraints within `excludedSubtrees` or `permittedSubtrees`. A remote attacker can exploit this by crafting a leaf certificate with casing differences in the Subject Alternative Name (SAN), leading to a policy bypass where a certificate that should be rejected is instead accepted. This could result in unauthorized access or information disclosure.
- Products
- gnutls, hardened images, openshift container platform, enterprise linux
- Weakness
- CWE-178
- Vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
In the news
3 storiesMultiple TLS libraries: X.509 Name Constraints enforcement bypasses (CVE-2026-34073, CVE-2026-3833, CVE-2026-5263, CVE-2026-33810; CERT/CC VU#573195, VU#948176, VU#410595)
Multiple TLS libraries bypass X.509 name-constraint checks, tracked in four CVEs and three CERT/CC notes.
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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.
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