WolfSSL

A specially crafted x509 certificate can cause a single out of bounds byte overwrite in wolfSSL through 3.10.2 resulting in potential certificate validation vulnerabilities, denial of service and possible remote code execution. In order to trigger this vulnerability, the…

In the OpenSSL compatibility layer implementation, the function RAND_poll() was not behaving as expected and leading to the potential for predictable values returned from RAND_bytes() after fork() is called. This can lead to weak or predictable random numbers generated in…

wolfSSL CyaSSL before 2.9.4 allows remote attackers to have unspecified impact via multiple calls to the CyaSSL_read function which triggers an out-of-bounds read when an error occurs, related to not checking the return code and MAC verification failure.

The SSL 3 HMAC functionality in wolfSSL CyaSSL 2.5.0 before 2.9.4 does not check the padding length when verification fails, which allows remote attackers to have unspecified impact via a crafted HMAC, which triggers an out-of-bounds read.

The DoAlert function in the (1) TLS and (2) DTLS implementations in wolfSSL CyaSSL before 2.9.4 allows remote attackers to have unspecified impact and vectors, which trigger memory corruption or an out-of-bounds read.

In wolfSSL through 4.1.0, there is a missing sanity check of memory accesses in parsing ASN.1 certificate data while handshaking. Specifically, there is a one-byte heap-based buffer over-read in CheckCertSignature_ex in wolfcrypt/src/asn.c.

wolfSSL 4.1.0 has a one-byte heap-based buffer over-read in DecodeCertExtensions in wolfcrypt/src/asn.c because reading the ASN_BOOLEAN byte is mishandled for a crafted DER certificate in GetLength_ex.

wolfSSL 4.0.0 has a Buffer Overflow in DoPreSharedKeys in tls13.c when a current identity size is greater than a client identity size. An attacker sends a crafted hello client packet over the network to a TLSv1.3 wolfSSL server. The length fields of the packet: record length,…

examples/benchmark/tls_bench.c in a benchmark tool in wolfSSL through 3.15.7 has a heap-based buffer overflow.

A certificate verification error in wolfSSL when building with the WOLFSSL_SYS_CA_CERTS and WOLFSSL_APPLE_NATIVE_CERT_VALIDATION options results in the wolfSSL client failing to properly verify the server certificate's domain name, allowing any certificate issued by a trusted…

In wolfSSL before 5.5.2, if callback functions are enabled (via the WOLFSSL_CALLBACKS flag), then a malicious TLS 1.3 client or network attacker can trigger a buffer over-read on the heap of 5 bytes. (WOLFSSL_CALLBACKS is only intended for debugging.)

Use-after-free in PQC hybrid key-share handling. This is an incomplete-fix follow-up to CVE-2026-5460 (released in 5.9.1): a malicious TLS 1.3 server sending a truncated PQC hybrid KeyShare can still trigger the error cleanup path to operate on freed memory.

Heap buffer overflow in DTLS 1.3 ACK message processing. A remote attacker can send a crafted DTLS 1.3 ACK message that triggers a heap buffer overflow.

Two potential heap out-of-bounds write locations existed in DecodeObjectId() in wolfcrypt/src/asn.c. First, a bounds check only validates one available slot before writing two OID arc values (out[0] and out[1]), enabling a 2-byte out-of-bounds write when outSz equals 1. Second,…

Heap-based buffer overflow in the KCAPI ECC code path of wc_ecc_import_x963_ex() in wolfSSL wolfcrypt allows a remote attacker to write attacker-controlled data past the bounds of the pubkey_raw buffer via a crafted oversized EC public key point. The WOLFSSL_KCAPI_ECC code path…

Stack Buffer Overflow in wc_HpkeLabeledExtract via Oversized ECH Config. A vulnerability existed in wolfSSL 5.8.4 ECH (Encrypted Client Hello) support, where a maliciously crafted ECH config could cause a stack buffer overflow on the client side, leading to potential remote…

Heap Overflow in TLS 1.3 ECH parsing. An integer underflow existed in ECH extension parsing logic when calculating a buffer length, which resulted in writing beyond the bounds of an allocated buffer. Note that in wolfSSL, ECH is off by default, and the ECH standard is still…

Two buffer overflow vulnerabilities existed in the wolfSSL CRL parser when parsing CRL numbers: a heap-based buffer overflow could occur when improperly storing the CRL number as a hexadecimal string, and a stack-based overflow for sufficiently sized CRL numbers. With…

RsaPad_PSS in wolfcrypt/src/rsa.c in wolfSSL before 4.6.0 has an out-of-bounds write for certain relationships between key size and digest size.

wolfSSL prior to version 3.12.2 provides a weak Bleichenbacher oracle when any TLS cipher suite using RSA key exchange is negotiated. An attacker can recover the private key from a vulnerable wolfSSL application. This vulnerability is referred to as "ROBOT."

A vulnerability in the handling of verify_mode = CERT_REQUIRED in the wolfssl Python package (wolfssl-py) causes client certificate requirements to not be fully enforced.  Because the WOLFSSL_VERIFY_FAIL_IF_NO_PEER_CERT flag was not included, the behavior effectively matched…

Heap buffer overread in wc_PKCS7_DecodeEnvelopedData when parsing crafted PKCS7 EnvelopedData. This could theoretically be triggered by attacker-supplied data delivered via S/MIME or CMS.

Dual-Algorithm CertificateVerify out-of-bounds read. When processing a dual-algorithm CertificateVerify message, an out-of-bounds read can occur on crafted input. This can only occur when --enable-experimental and --enable-dual-alg-certs is used when building wolfSSL.

In TLSX_EchChangeSNI, the ctx->extensions branch set extensions unconditionally even when TLSX_Find returned NULL. This caused TLSX_UseSNI to attach the attacker-controlled publicName to the shared WOLFSSL_CTX when no inner SNI was configured. TLSX_EchRestoreSNI then failed to…

Missing hash/digest size and OID checks allow digests smaller than allowed when verifying ECDSA certificates, or smaller than is appropriate for the relevant key type, to be accepted by signature verification functions. This could lead to reduced security of ECDSA…

wolfSSL before 3.10.2 has an out-of-bounds memory access with loading crafted DH parameters, aka a buffer overflow triggered by a malformed temporary DH file.

In wolfSSL before 5.5.1, malicious clients can cause a buffer overflow during a TLS 1.3 handshake. This occurs when an attacker supposedly resumes a previous TLS session. During the resumption Client Hello a Hello Retry Request must be triggered. Both Client Hellos are required…

wolfssl before 3.2.0 has a server certificate that is not properly authorized for server authentication.

wolfssl before 3.2.0 does not properly authorize CA certificate for signing other certificates.

wolfssl before 3.2.0 does not properly issue certificates for a server's hostname.

In wolfSSL 4.1.0 through 4.2.0c, there are missing sanity checks of memory accesses in parsing ASN.1 certificate data while handshaking. Specifically, there is a one-byte heap-based buffer overflow inside the DecodedCert structure in GetName in wolfcrypt/src/asn.c because the…

wolfSSL before 3.11.0 does not prevent wc_DhAgree from accepting a malformed DH key.

wolfSSL (formerly CyaSSL) before 3.6.8 allows remote attackers to cause a denial of service (resource consumption or traffic amplification) via a crafted DTLS cookie in a ClientHello message.

wolfSSL_X509_verify_cert in the OpenSSL compatibility layer accepts a certificate chain in which the leaf's signature is not checked, if the attacker supplies an untrusted intermediate with Basic Constraints `CA:FALSE` that is legitimately signed by a trusted root. An attacker…

In wolfSSL's EVP layer, the ChaCha20-Poly1305 AEAD decryption path in wolfSSL_EVP_CipherFinal (and related EVP cipher finalization functions) fails to verify the authentication tag before returning plaintext to the caller. When an application uses the EVP API to perform…

wolfSSL's ECCSI signature verifier `wc_VerifyEccsiHash` decodes the `r` and `s` scalars from the signature blob via `mp_read_unsigned_bin` with no check that they lie in `[1, q-1]`. A crafted forged signature could verify against any message for any identity, using only…

An integer underflow issue exists in wolfSSL when parsing the Subject Alternative Name (SAN) extension of X.509 certificates. A malformed certificate can specify an entry length larger than the enclosing sequence, causing the internal length counter to wrap during parsing. This…

A heap-buffer-overflow vulnerability exists in wolfSSL's wolfSSL_d2i_SSL_SESSION() function. When deserializing session data with SESSION_CERTS enabled, certificate and session id lengths are read from an untrusted input without bounds validation, allowing an attacker to…

An issue was discovered in wolfSSL before 4.5.0, when single precision is not employed. Local attackers can conduct a cache-timing attack against public key operations. These attackers may already have obtained sensitive information if the affected system has been used for…

A stack buffer overflow exists in wolfSSL's PKCS7 implementation in the wc_PKCS7_DecryptOri() function in wolfcrypt/src/pkcs7.c. When processing a CMS EnvelopedData message containing an OtherRecipientInfo (ORI) recipient, the function copies an ASN.1-parsed OID into a fixed…

Fault Injection vulnerability in wc_ed25519_sign_msg function in wolfssl/wolfcrypt/src/ed25519.c in WolfSSL wolfssl5.6.6 on Linux/Windows allows remote attacker co-resides in the same system with a victim process to disclose information and escalate privileges via Rowhammer…

wolfSSL before 4.5.0 mishandles TLS 1.3 server data in the WAIT_CERT_CR state, within SanityCheckTls13MsgReceived() in tls13.c. This is an incorrect implementation of the TLS 1.3 client state machine. This allows attackers in a privileged network position to completely…

wc_Blake2bHmacFinal and wc_Blake2sHmacFinal discard the message when the key length exceeds the block size, producing a MAC that is independent of the input. When the supplied key is longer than the BLAKE2 block size the key-hashing branch reinitialized the running hash state,…

iPAddress name constraints bypass when WOLFSSL_IP_ALT_NAME is not defined. IP address name constraints are not enforced in that configuration, allowing a certificate to bypass an issuing CA's IP address constraints.

PKCS7_verify signer confusion allows forged signatures, where the signer associated with a signature is not correctly bound, permitting a forged signature to be accepted.

HMAC zero-length tag forgery in EVP_DigestVerifyFinal, where a zero-length tag could be accepted as valid during HMAC verification. In the OpenSSL-compatibility HMAC verify path the supplied signature length was only checked as not exceeding the MAC length, so a zero-length or…

Out-of-bounds write in SetSuitesHashSigAlgo when processing an oversized signature algorithms list, allowing a write past the bounds of the destination buffer.

Missing SNI/ALPN binding on stateful (session-ID) resumption, which previously skipped the binding check performed for ticket-based resumption. A cached session could be resumed under a different SNI/ALPN than originally negotiated and, where client-authentication policy differs…

X.509 name constraint bypass via the Subject Common Name when treated as a DNS-type name. A certificate whose Subject CN violates an issuing CA's DNS name constraints could be accepted.

A heap buffer overflow could occur in the DTLS 1.3 ACK serialization path before the connecting peer is authenticated. The buffer overflow was due to an integer truncation when computing the length of the ACK record-number list, causing an undersized buffer to be allocated and…