CVE-2026-75806
MediumCVSS 5.3Summary
An established DTLS 1.2 association using an AEAD cipher suite can be terminated by a single unauthenticated datagram whose encrypted fragment is shorter than the mandatory explicit IV and authentication tag overhead. The record layer passes the record length to the cipher before checking it is long enough, causing an internal error instead of treating the record as failed authentication.
Risk Assessment
An attacker who can send a datagram to an existing DTLS 1.2 association can tear it down without knowing any key material, causing a denial of service limited to that association. There is no memory safety or confidentiality impact.
Recommendation
Apply the vendor patch that validates record length against explicit IV and tag length before AEAD processing, so DTLS silently discards short records. Update the TLS/DTLS library to a patched version.
Other vulnerabilities in OpenSSL
See all- CVE-2026-84784High
A malicious remote peer can flood the local QUIC stack with NEW_CONNECTION_ID frames by bypassing a limit on connection IDs. This causes RETIRE_CONN_ID frames to be sent and, with withheld ACKs, can allocate about 400 MB of memory.
- CVE-2026-84783High
OpenSSL 4.0 contains a use-after-free vulnerability (CWE-416) in the caching of X.509 certificate extensions. When several threads concurrently use the same certificate for the first time, one thread may free the cached extension data while another thread is still using it. This can crash the process, resulting in a Denial of Service.
- CVE-2026-84782High
The DTLS retransmission logic incorrectly handles a handshake message write that is suspended part-way through. The retransmitted message can be read past the message buffer, disclosing heap memory or causing a crash and Denial of Service.
- CVE-2026-77696Low
SM2 signature generation uses non-constant-time arithmetic on secret values, forming a timing side-channel. An attacker able to measure SM2 signing times may learn information about the per-signature secret nonce, which over many signatures can lead to recovery of the private key. Applications performing SM2 signature generation are affected on all platforms.
- CVE-2026-75805Medium
A NULL pointer dereference vulnerability in the OpenSSL CMP client. When a client requests certificate revocation based on a PKCS#10 CSR and the server returns a specially crafted certificate name in its response, the client reads from a NULL pointer and crashes. Only clients that identify the certificate via CSR (e.g. 'openssl cmp -cmd rr -csr' or OSSL_CMP_exec_RR_ses() with OSSL_CMP_CTX_set1_p10CSR()) are affected.
- CVE-2026-75804Medium
The OpenSSL QUIC stack does not enforce connection-level flow control for streams. A malicious remote peer can send more bytes as long as they fit within stream flow control limits, leading to excessive memory allocation.
- CVE-2026-72897High
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 the end of an internal array if the replacement context knows about more provider signature algorithms than the context the connection was created from. A remote peer may be able to cause a small out-of-bounds read, and in some circumstances a fixed-value out-of-bounds write, on the server heap, potentially leading to a Denial of Service.
- CVE-2026-54875Low
OpenSSL's optimized scalar point multiplication implementation for SM2 private key operations on ARM64 and RISC-V platforms is not constant-time. Conditional branches and table lookups depend on the bits of the secret scalar, so execution time and cache-access patterns leak information about the private key or signature nonce.
- CVE-2026-54873High
A vulnerability in the QUIC implementation in OpenSSL allows a remote attacker to keep allocated packet buffer memory for an extended period by sending specially crafted packets. The issue stems from missing resource allocation limits (CWE-770), potentially leading to excessive memory consumption.
- CVE-2026-54872Low
The generic elliptic-curve scalar multiplication used for ECDSA and SM2 signature operations with curves lacking a dedicated implementation leaks information about the secret nonce through timing. An attacker measuring signing times may learn the nonce, which over many signatures can lead to private key recovery.
Original NVD description (English source)
Issue summary: An established DTLS 1.2 association using an AEAD cipher suite can be terminated by a single unauthenticated datagram whose encrypted fragment is shorter than the mandatory explicit IV and authentication tag overhead. Impact summary: An attacker who can send a datagram that is routed to an existing DTLS 1.2 association can tear that association down without knowing any key material. This is a Denial of Service limited to the targeted association. There is no memory safety or confidentiality impact. CWE: CWE-1284: Improper Validation of Specified Quantity in Input Description: In TLS 1.2 and DTLS 1.2 every record protected by an AEAD cipher suite carries an explicit IV followed by the ciphertext and an authentication tag. When decrypting such a record the record layer passed the record length to the cipher implementation before checking that the record was long enough to contain the explicit IV and the tag. For a record shorter than that overhead the cipher implementation rejected the impossible length, and the record layer treated this as an internal failure and raised a fatal internal_error alert instead of treating the record as one that failed authentication. In TLS 1.2 the same record causes a fatal internal_error alert instead of the expected bad_record_mac alert. Since any undecryptable record already terminates a TLS connection, this is a protocol conformance issue rather than a security issue in TLS. The fix validates the record length against the explicit IV and tag length before any AEAD processing, so that TLS reports bad_record_mac and DTLS silently discards the record. FIPS impact: no The affected code is outside the FIPS module boundary.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS