GnuTLS Vulnerability Bulletin: Multiple CVEs (RCE, ID Bypass, DoS)

Vulnerability Overview The GnuTLS Transport Layer Security Library contains multiple security vulnerabilities involving certificate verification, memory management, protocol implementation, and other aspects. These vulnerabilities can lead to serious security issues, such as privilege escalation, data leakage, and denial of service. Scope of Impact Certificate Verification Issues: Multiple vulnerabilities involve issues in the certificate verification process, such as certificate chain verification and certificate revocation checks. Memory Management Issues: Some vulnerabilities involve memory overflow and buffer overflow, which may lead to program crashes or execution of malicious code. Protocol Implementation Issues: Vulnerabilities in the TLS/DTLS protocol implementation may lead to security issues such as man-in-the-middle (MITM) attacks and session hijacking. Remediation Version Upgrade: The remediation for most vulnerabilities is to upgrade to the latest version of GnuTLS (e.g., 3.8.13 or later). Apply Patches: For certain specific versions, specific patches need to be applied. Configuration Adjustment: Some vulnerabilities require mitigation through configuration adjustments, such as disabling certain features or setting specific parameters. Specific Vulnerability Details CVE-2026-42014 Description: When changing the Security Officer PIN, if the parameter of is NULL, a use-after-free issue may occur. Remediation: Upgrade to GnuTLS 3.8.13 or later. CVE-2026-42013 Description: When verifying a certificate with extended certificate alternative names, if the certificate alternative names do not match the DNS hostname, certificate misuse may occur. Remediation: Upgrade to GnuTLS 3.8.13 or later. CVE-2026-42012 Description: When verifying a certificate containing URI or SRV certificate alternative names, if the certificate alternative names do not match the Common Name, certificate misuse may occur. Remediation: Upgrade to GnuTLS 3.8.13 or later. CVE-2026-42011 Description: When a previous CA has excluded name constraints, the allowed name constraints are incorrectly ignored, leading to name constraint bypass. Remediation: Upgrade to GnuTLS 3.8.13 or later. CVE-2026-3833 Description: Domain name comparison may error when handling constraints containing NULL characters, resulting in acceptance of domains that should have been rejected. Remediation: Upgrade to GnuTLS 3.8.13 or later. CVE-2026-42010 Description: Servers configured to use RSA-PSK incorrectly accept usernames containing NULL characters, leading to authentication bypass. Remediation: Upgrade to GnuTLS 3.8.13 or later. CVE-2026-33845 Description: A remotely triggerable underflow in the DTLS reassembly code may lead to heap overflow. Remediation: Upgrade to GnuTLS 3.8.13 or later. CVE-2026-42009 Description: The comparison function used to sort DTLS packets may produce undefined behavior when sequence numbers are duplicated. Remediation: Upgrade to GnuTLS 3.8.13 or later. CVE-2026-5419 Description: PKCS#1 padding check is not constant-time during decryption, potentially leaking padding bytes via timing differences. Remediation: Upgrade to GnuTLS 3.8.13 or later. CVE-2026-3832 Description: When verifying a certificate in a multi-entry OCSP response, the revocation status always checks the first entry instead of the matching certificate. Remediation: Upgrade to GnuTLS 3.8.13 or later. CVE-2026-42015 Description: If a PKCS#12 package contains only 32 elements, memory beyond the bounds of its internal array may be written to. Remediation: Upgrade to GnuTLS 3.8.13 or later. CVE-2026-5260 Description: When using a PKCS#11 token with RSA key backup, extra short pre-master secrets sent by the client may cause heap overflow in the RSA key. Remediation: Upgrade to GnuTLS 3.8.13 or later. CVE-2026-33846 Description: GnuTLS does not check the message length for consistency of DTLS fragments, potentially leading to heap overflow. Remediation: Upgrade to GnuTLS 3.8.13 or later. CVE-2025-14831 Description: Verifying a certificate with a pathological number of name constraints may lead to denial of service and resource exhaustion. Remediation: Upgrade to GnuTLS 3.8.12 or later. CVE-2026-1584 Description: TLS 1.3 renegotiation attempts using invalid PSK binding values may lead to denial of service attacks. Remediation: Upgrade to GnuTLS 3.8.12 or later. CVE-2025-9820 Description: When initializing a PKCS#11 token, if the passed token label exceeds 32 characters, memory beyond the boundaries of stack-allocated memory may be written to. Remediation: Upgrade to GnuTLS 3.8.1 or later. CVE-2025-6395 Description: In TLS 1.3 handshakes involving a Hello Retry Request and a second Client Hello, GnuTLS may dereference a NULL pointer. Remediation: Upgrade to GnuTLS 3.8.10 or later. CVE-2025-32990 Description: When calling the program, if the template file contains multiple string pairs, it may lead to a NULL pointer out-of-bounds access. Remediation: Upgrade to GnuTLS 3.8.1

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GnuTLS Vulnerability Bulletin: Multiple CVEs (RCE, ID Bypass, DoS)