JLSEC-2026-523

A vulnerability found in gnutls. This security flaw happens because of a double free error occurs during verification of pkcs7 signatures in gnutlspkcs7verify function...

gnutls: gnutls: Information disclosure via timing side-channel in PKCS#7 padding removal

A flaw was found in gnutls. The PKCS7 padding check, performed during decryption, was not constant-time. This timing side-channel could allow a remote attacker to potentially leak sensitive information about the padding bytes through observable timing differences. This vulnerability is a form of...

Important: Red Hat Security Advisory: gnutls security update

An update for gnutls is now available for Red Hat Enterprise Linux 9. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System CVSS base score, which gives a detailed severity rating, is available for each vulnerability from the...

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: Use-after-free in gnutls_pkcs11_token_set_pin

A flaw was found in GnuTLS. The gnutlspkcs11tokensetpin function, used for changing the Security Officer PIN, can lead to a use-after-free vulnerability. This occurs when an attacker attempts to change the PIN with a NULL old PIN for a token that lacks a protected authentication path...

gnutls: GnuTLS: Denial of Service via DTLS zero-length fragment

A flaw in GnuTLS DTLS handshake parsing allows malformed fragments with zero length and non-zero offset, leading to an integer underflow during reassembly and resulting in an out-of-bounds read. This issue is remotely exploitable and may cause information disclosure or denial of service...

gnutls: GnuTLS: Denial of Service via heap buffer overflow in DTLS handshake fragment reassembly

A heap buffer overflow vulnerability exists in the DTLS handshake fragment reassembly logic of GnuTLS. The issue arises in mergehandshakepacket where incoming handshake fragments are matched and merged based solely on handshake type, without validating that the messagelength field remains...

gnutls: gnutls: Memory corruption due to off-by-one error in PKCS#12 bag handling

A flaw was found in gnutls. An off-by-one error exists in the PKCS12 bag element bounds check. This vulnerability allows an remote attacker to write past the internal array of a PKCS12 bag when appending to a bag that already contains 32 elements. This memory corruption could lead to a denial of...

gnutls: gnutls: Denial of Service via DTLS packet reordering vulnerability

A flaw was found in gnutls. A remote attacker could exploit an issue in the Datagram Transport Layer Security DTLS packet reordering logic. The comparator function, responsible for ordering DTLS packets by sequence numbers, did not correctly handle packets with duplicate sequence numbers. This...

gnutls: gnutls: Security bypass due to incorrect name constraint handling

A flaw was found in gnutls. This vulnerability occurs because permitted name constraints were incorrectly ignored when previous Certificate Authorities CAs only had excluded name constraints. A remote attacker could exploit this to bypass critical name constraint checks during certificate...

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: Information disclosure via heap overread in RSA key exchange

A flaw was found in libgnutls. A remote attacker, by sending an extremely short premaster secret during an RSA key exchange to a server using an RSA key backed by a PKCS11 token, could trigger a short heap overread. This memory corruption vulnerability could lead to information disclosure...

gnutls: gnutls: Security bypass allows acceptance of revoked server certificates via crafted OCSP response

A flaw was found in gnutls. A remote attacker could exploit this vulnerability by presenting a specially crafted Online Certificate Status Protocol OCSP response during a TLS handshake. Due to a logic error in how gnutls processes multi-record OCSP responses, a client with OCSP verification enabl...

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...

gnutls: gnutls: Authentication Bypass via NUL Character in Username

A flaw was found in gnutls. Servers configured with RSA-PSK Rivest–Shamir–Adleman – Pre-Shared Key wrongfully matched usernames containing a NUL character with truncated usernames. A remote attacker could exploit this by sending a specially crafted username, leading to an authentication bypass...

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: Use-after-free in gnutls_pkcs11_token_set_pin

A flaw was found in GnuTLS. The gnutlspkcs11tokensetpin function, used for changing the Security Officer PIN, can lead to a use-after-free vulnerability. This occurs when an attacker attempts to change the PIN with a NULL old PIN for a token that lacks a protected authentication path...

gnutls: GnuTLS: Denial of Service via DTLS zero-length fragment

A flaw in GnuTLS DTLS handshake parsing allows malformed fragments with zero length and non-zero offset, leading to an integer underflow during reassembly and resulting in an out-of-bounds read. This issue is remotely exploitable and may cause information disclosure or denial of service...

gnutls: gnutls: Denial of Service via DTLS packet reordering vulnerability

A flaw was found in gnutls. A remote attacker could exploit an issue in the Datagram Transport Layer Security DTLS packet reordering logic. The comparator function, responsible for ordering DTLS packets by sequence numbers, did not correctly handle packets with duplicate sequence numbers. This...

gnutls: gnutls: Security bypass allows acceptance of revoked server certificates via crafted OCSP response

A flaw was found in gnutls. A remote attacker could exploit this vulnerability by presenting a specially crafted Online Certificate Status Protocol OCSP response during a TLS handshake. Due to a logic error in how gnutls processes multi-record OCSP responses, a client with OCSP verification enabl...