This page lists publicly disclosed CVE vulnerabilities affecting gnu gnutls (linked via NVD CPE). Each row includes severity scores, summaries, and publication dates to help identify and analyze security issues.
| CVE | Summary | Source | Max CVSS | EPSS % | Published | Updated |
|---|---|---|---|---|---|---|
| CVE-2026-42009 | 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 could lead to unstable packet ordering or undefined behavior, resulting in a denial of service. | [email protected] | 7.5 | 0.71% | 2026-05-18 | 2026-06-08 |
| CVE-2026-42010 | 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. This vulnerability allows an attacker to gain unauthorized access by circumventing the authentication process. | [email protected] | 7.1 | 0.06% | 2026-05-07 | 2026-06-10 |
| CVE-2026-3833 | 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 unaut | [email protected] | 6.5 | 0.18% | 2026-04-30 | 2026-06-02 |
| CVE-2026-3832 | 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 enabled may incorrectly accept a revoked server certificate, potentially leading to a compromise of trust. | [email protected] | 3.7 | 0.02% | 2026-04-30 | 2026-06-02 |
| CVE-2026-33845 | 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. | [email protected] | 7.5 | 0.06% | 2026-04-30 | 2026-06-02 |
| CVE-2026-1584 | A flaw was found in gnutls. A remote, unauthenticated attacker can exploit this vulnerability by sending a specially crafted ClientHello message with an invalid Pre-Shared Key (PSK) binder value during the TLS handshake. This can lead to a NULL pointer dereference, causing the server to crash and resulting in a remote Denial of Service (DoS) condition. | [email protected] | 7.5 | 0.08% | 2026-04-09 | 2026-05-03 |
| CVE-2025-32990 | A heap-buffer-overflow (off-by-one) flaw was found in the GnuTLS software in the template parsing logic within the certtool utility. When it reads certain settings from a template file, it allows an attacker to cause an out-of-bounds (OOB) NULL pointer write, resulting in memory corruption and a denial-of-service (DoS) that could potentially crash the system. | [email protected] | 6.5 | 0.29% | 2025-07-10 | 2026-04-20 |
| CVE-2025-32989 | A heap-buffer-overread vulnerability was found in GnuTLS in how it handles the Certificate Transparency (CT) Signed Certificate Timestamp (SCT) extension during X.509 certificate parsing. This flaw allows a malicious user to create a certificate containing a malformed SCT extension (OID 1.3.6.1.4.1.11129.2.4.2) that contains sensitive data. This issue leads to the exposure of confidential information when GnuTLS verifies certificates from certain websites when the certificate (SCT) is not checke | [email protected] | 5.3 | 0.09% | 2025-07-10 | 2026-05-12 |
| CVE-2025-32988 | A flaw was found in GnuTLS. A double-free vulnerability exists in GnuTLS due to incorrect ownership handling in the export logic of Subject Alternative Name (SAN) entries containing an otherName. If the type-id OID is invalid or malformed, GnuTLS will call asn1_delete_structure() on an ASN.1 node it does not own, leading to a double-free condition when the parent function or caller later attempts to free the same structure. This vulnerability can be triggered using only public GnuTLS APIs and m | [email protected] | 6.5 | 0.23% | 2025-07-10 | 2026-05-12 |
| CVE-2024-0567 | A vulnerability was found in GnuTLS, where a cockpit (which uses gnuTLS) rejects a certificate chain with distributed trust. This issue occurs when validating a certificate chain with cockpit-certificate-ensure. This flaw allows an unauthenticated, remote client or attacker to initiate a denial of service attack. | [email protected] | 7.5 | 1.60% | 2024-01-16 | 2024-11-21 |
| CVE-2024-0553 | A vulnerability was found in GnuTLS. The response times to malformed ciphertexts in RSA-PSK ClientKeyExchange differ from the response times of ciphertexts with correct PKCS#1 v1.5 padding. This issue may allow a remote attacker to perform a timing side-channel attack in the RSA-PSK key exchange, potentially leading to the leakage of sensitive data. CVE-2024-0553 is designated as an incomplete resolution for CVE-2023-5981. | [email protected] | 7.5 | 1.03% | 2024-01-16 | 2026-03-24 |
| CVE-2023-5981 | A vulnerability was found that the response times to malformed ciphertexts in RSA-PSK ClientKeyExchange differ from response times of ciphertexts with correct PKCS#1 v1.5 padding. | [email protected] | 5.9 | 0.84% | 2023-11-28 | 2026-03-25 |
| CVE-2023-0361 | A timing side-channel in the handling of RSA ClientKeyExchange messages was discovered in GnuTLS. This side-channel can be sufficient to recover the key encrypted in the RSA ciphertext across a network in a Bleichenbacher style attack. To achieve a successful decryption the attacker would need to send a large amount of specially crafted messages to the vulnerable server. By recovering the secret from the ClientKeyExchange message, the attacker would be able to decrypt the application data exchan | [email protected] | 7.4 | 3.62% | 2023-02-15 | 2025-03-19 |
| CVE-2021-4209 | A NULL pointer dereference flaw was found in GnuTLS. As Nettle's hash update functions internally call memcpy, providing zero-length input may cause undefined behavior. This flaw leads to a denial of service after authentication in rare circumstances. | [email protected] | 6.5 | 0.37% | 2022-08-24 | 2024-11-21 |
| CVE-2022-2509 | A vulnerability found in gnutls. This security flaw happens because of a double free error occurs during verification of pkcs7 signatures in gnutls_pkcs7_verify function. | [email protected] | 7.5 | 0.63% | 2022-08-01 | 2025-12-02 |
| CVE-2021-20232 | A flaw was found in gnutls. A use after free issue in client_send_params in lib/ext/pre_shared_key.c may lead to memory corruption and other potential consequences. | [email protected] | 9.8 | 0.84% | 2021-03-12 | 2025-12-03 |
| CVE-2021-20231 | A flaw was found in gnutls. A use after free issue in client sending key_share extension may lead to memory corruption and other consequences. | [email protected] | 9.8 | 1.20% | 2021-03-12 | 2024-11-21 |
| CVE-2020-24659 | An issue was discovered in GnuTLS before 3.6.15. A server can trigger a NULL pointer dereference in a TLS 1.3 client if a no_renegotiation alert is sent with unexpected timing, and then an invalid second handshake occurs. The crash happens in the application's error handling path, where the gnutls_deinit function is called after detecting a handshake failure. | [email protected] | 7.5 | 3.63% | 2020-09-04 | 2024-11-21 |
| CVE-2020-13777 | GnuTLS 3.6.x before 3.6.14 uses incorrect cryptography for encrypting a session ticket (a loss of confidentiality in TLS 1.2, and an authentication bypass in TLS 1.3). The earliest affected version is 3.6.4 (2018-09-24) because of an error in a 2018-09-18 commit. Until the first key rotation, the TLS server always uses wrong data in place of an encryption key derived from an application. | [email protected] | 7.4 | 1.21% | 2020-06-04 | 2024-11-21 |
| CVE-2020-11501 | GnuTLS 3.6.x before 3.6.13 uses incorrect cryptography for DTLS. The earliest affected version is 3.6.3 (2018-07-16) because of an error in a 2017-10-06 commit. The DTLS client always uses 32 '\0' bytes instead of a random value, and thus contributes no randomness to a DTLS negotiation. This breaks the security guarantees of the DTLS protocol. | [email protected] | 7.4 | 11.49% | 2020-04-03 | 2024-11-21 |