Openssl vulnerabilities

By year

Bars are flaws published each year; the red part is the share attackers have used.

Exploited Openssl flaws

These are on CISA’s Known Exploited Vulnerabilities list, newest first. If you run any of these products, these come before everything else.

• CVE-2014-0160 OpenSSL Information DisclosureExploited since May 4, 2022 · CVSS 7.5

Latest high and critical flaws

• CVE-2026-84784 Issue summary: A malicious remote peer may flood the local QUIC stack with NEW_CONNECTION_ID frames by avoiding a limit check on how many connection IDs the remHigh 7.5 · Sep 29, 2026
• CVE-2026-84783 Issue summary: The first concurrent use of the same X.509 certificate by several threads may cause its cached extension data to be freed while another thread isHigh 7.5 · Sep 29, 2026
• CVE-2026-84782 Issue summary: The DTLS retransmission logic does not correctly handle a handshake message write that is suspended part-way through.High 8.2 · Sep 29, 2026
• CVE-2026-72897 Issue summary: A TLS server that calls SSL_set_SSL_CTX() to switch a connection to a different SSL_CTX part way through a handshake may access memory beyond theHigh 7.5 · Sep 29, 2026
• CVE-2026-54873 Issue summary: QUIC process may keep memory for QUIC packet buffer for much longer period than necessary.High 7.5 · Sep 29, 2026
• CVE-2026-75803 Issue summary: ChaCha20-Poly1305 and AES-OCB decryption with an empty ciphertext can report success without verifying the supplied authentication tag when the oCritical 9.1 · Aug 25, 2026
• CVE-2026-63076 Issue summary: OpenSSL CMP password based protection verification only checks whether the protectionAlg parameter was not NULL and not its ASN.1 type, before trHigh 7.5 · Aug 25, 2026
• CVE-2026-63075 Issue summary: When OpenSSL processes QUIC traffic from a peer that repeatedly sends ack-eliciting packets while not acknowledging ACK-only responses, the QUIC High 7.5 · Aug 25, 2026
• CVE-2026-63073 Issue summary: OpenSSL CMP response validation passed an unexpected response sender distinguished name directly as the format string to `ERR_raise_data()`.Critical 9.8 · Aug 25, 2026
• CVE-2026-63072 Issue summary: OpenSSL CMS decryption sizes the key-unwrap output buffer based on querying the unwrapped key size, but the AES-WRAP-PAD unwrap primitive can wriHigh 7.5 · Aug 25, 2026
• CVE-2026-54874 Issue summary: Receiving a DTLS record for a future epoch while a handshake is in progress causes OpenSSL to buffer far more memory than the record itself requiHigh 7.5 · Aug 25, 2026
• CVE-2026-18798 Issue summary: QUIC server may double free QRX (QUIC record layer RX) object when channel creation fails for initial packet.High 7.5 · Aug 25, 2026
• CVE-2026-14457 Issue summary: In a server or client configuration with RFC7250 Raw Public Keys (RPKs) enabled, and only the private key (with no associated certificate) configHigh 7.5 · Aug 25, 2026
• CVE-2026-14456 Issue summary: When an OpenSSL QUIC server (Listener SSL object) processes valid QUIC Initial packets for unknown destination connection IDs, it can allocate anHigh 7.5 · Aug 13, 2026
• CVE-2026-54876 Issue summary: A malicious TLS server can cause a memory leak in a TLS client that has enabled OCSP response checking by sending an OCSP response that contains High 7.5 · Aug 5, 2026
• CVE-2026-9076 Issue summary: When CMS password-based decryption (RFC 3211 / PWRI key unwrap) processes attacker-supplied CMS data, an attacker-chosen stream-mode KEK cipher cHigh 7.5 · Jun 9, 2026
• CVE-2026-7383 Issue summary: A signed integer overflow when sizing the destination buffer for Unicode output in ASN1_mbstring_ncopy() can lead to a heap buffer overflow.High 8.1 · Jun 9, 2026
• CVE-2026-45447 Issue summary: A specially crafted PKCS#7 or S/MIME signed message could trigger a use-after-free during PKCS#7 signature verification.High 8.8 · Jun 9, 2026
• CVE-2026-45445 Issue summary: When an application drives an AES-OCB context through the public EVP_Cipher() one-shot interface, the application-supplied initialisation vector High 7.5 · Jun 9, 2026
• CVE-2026-42765 Issue summary: When a partial-chain certificate verification is enabled together with OCSP response checking for the whole chain, a NULL dereference will happenHigh 7.5 · Jun 9, 2026
• CVE-2026-42764 Issue summary: Receiving a QUIC initial packet with an invalid token may trigger a NULL pointer dereference in the OpenSSL QUIC server with address validation dHigh 7.5 · Jun 9, 2026
• CVE-2026-34183 Issue summary: Remote peer may exhaust heap memory of the QUIC server or client by flooding it with packets containing PATH_CHALLENGE frames.High 7.5 · Jun 9, 2026
• CVE-2026-34182 Issue Summary: Cryptographic Message Services (CMS) processing fails to perform sufficient input validation on the cipher and tag length fields of AuthEnvelopedCritical 9.1 · Jun 9, 2026
• CVE-2026-34181 Issue Summary: The PKCS#12 file processing fails to perform sufficient input validation for files that use Password-Based Message Authentication Code 1 (PBMAC1)High 7.4 · Jun 9, 2026
• CVE-2026-34180 Issue summary: Parsing a crafted DER-encoded ASN.1 structure with a primitive element whose content exceeds 2 gigabytes in length may cause a heap buffer over-rHigh 7.5 · Jun 9, 2026