Important: Red Hat Security Advisory: gnutls and libtasn1 security update

An update for multiple packages is now available for Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions and Red Hat Enterprise Linux 8.8 Telecommunications Update Service. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability...

gnutls: GnuTLS: Denial of Service via excessive resource consumption during certificate verification

A flaw was found in GnuTLS. This vulnerability allows a denial of service DoS by excessive CPU Central Processing Unit and memory consumption via specially crafted malicious certificates containing a large number of name constraints and subject alternative names SANs...

gnutls: GnuTLS: Policy bypass due to case-sensitive nameConstraints comparison

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...

gnutls: gnutls: Certificate validation bypass due to improper handling of URI and SRV SANs

A flaw was found in gnutls. A remote attacker could exploit this vulnerability by presenting a specially crafted certificate that contains Uniform Resource Identifier URI or Service SRV Subject Alternative Names SANs. This could cause the certificate validation process to incorrectly fall back to...

gnutls: gnutls: Certificate validation bypass due to oversized Subject Alternative Name

A flaw was found in gnutls. When validating certificates, an oversized Subject Alternative Name SAN could cause the validation process to incorrectly fall back to checking the Common Name CN field. This could allow a remote attacker to bypass proper certificate validation, potentially leading to...

RHEL 9 : gnutls (RHSA-2026:32962)

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:32962 advisory. The gnutls packages provide the GNU Transport Layer Security GnuTLS library, which implements cryptographic algorithms and protocols such a...

CVE-2026-47778 Envoy: Embedded NUL in TLS DNS SAN Truncation in the Default TLS Certificate Validator. (Auth Bypass)

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.35.11, 1.36.7, 1.37.3, and 1.38.1, a structural flaw was identified in DefaultCertValidator::verifySubjectAltName where the extracted DNS SAN string is cast to a C-style string using .cstr before bei...

CVE-2026-47778 Envoy: Embedded NUL in TLS DNS SAN Truncation in the Default TLS Certificate Validator. (Auth Bypass)

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.35.11, 1.36.7, 1.37.3, and 1.38.1, a structural flaw was identified in DefaultCertValidator::verifySubjectAltName where the extracted DNS SAN string is cast to a C-style string using .cstr before bei...

PT-2026-52887

Name of the Vulnerable Software and Affected Versions Envoy versions prior to 1.35.11 Envoy versions prior to 1.36.7 Envoy versions prior to 1.37.3 Envoy versions prior to 1.38.1 Description A structural flaw exists in the DefaultCertValidator::verifySubjectAltName function. The issue occurs when...

RHEL 9 : gnutls (RHSA-2026:30004)

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:30004 advisory. The gnutls packages provide the GNU Transport Layer Security GnuTLS library, which implements cryptographic algorithms and protocols such a...

DEBIAN-CVE-2026-6731

X.509 name constraint bypass via the Subject Common Name when treated as a DNS-type name. A certificate whose Subject CN violates an issuing CA's DNS name constraints could be accepted...

UBUNTU-CVE-2026-6731

X.509 name constraint bypass via the Subject Common Name when treated as a DNS-type name. A certificate whose Subject CN violates an issuing CA's DNS name constraints could be accepted...

CVE-2026-12340

Out-of-bounds heap read during SM2/SM3 certificate signature verification. When parsing a certificate with an SM3wSM2 signature, the Subject Key Identifier computation reads the trailing 65 bytes of the public key without checking that the key is at least that long. A public key shorter than 65...

CVE-2026-6731

X.509 name constraint bypass via the Subject Common Name when treated as a DNS-type name. A certificate whose Subject CN violates an issuing CA's DNS name constraints could be accepted...

EUVD-2026-39555

X.509 name constraint bypass via the Subject Common Name when treated as a DNS-type name. A certificate whose Subject CN violates an issuing CA's DNS name constraints could be accepted...

CVE-2026-6731 X.509 name constraint bypass via Subject CN treated as a DNS name

X.509 name constraint bypass via the Subject Common Name when treated as a DNS-type name. A certificate whose Subject CN violates an issuing CA's DNS name constraints could be accepted...

CVE-2026-6731

X.509 name constraint bypass via the Subject Common Name when treated as a DNS-type name. A certificate whose Subject CN violates an issuing CA's DNS name constraints could be accepted...

CVE-2026-6731

CVE-2026-6731 describes an X.509 name constraint bypass where the Subject CN is treated as a DNS-type name, allowing a certificate to pass DNS constraints if the CN violates them. Public sources (NVD and related feeds) reference this bypass and provide CVSS metrics (v3.1: 7.5, Network, High impac...

CVE-2026-6731 X.509 name constraint bypass via Subject CN treated as a DNS name

X.509 name constraint bypass via the Subject Common Name when treated as a DNS-type name. A certificate whose Subject CN violates an issuing CA's DNS name constraints could be accepted...

CVE-2026-6731

X.509 name constraint bypass via the Subject Common Name when treated as a DNS-type name. A certificate whose Subject CN violates an issuing CA's DNS name constraints could be accepted...