X.509 trust-chain bypass in the OpenSSL compatibility certificate verifier (wolfSSLX509verifycert()). This affects only builds with --enable-opensslextra (OPENSSLEXTRA) and whose application validates certificates by calling X509verifycert() with caller-supplied untrusted intermediate certificates; for those users it is critical, otherwise the library is unaffected. In particular, native wolfSSL TLS/DTLS usage is not impacted. wolfSSL's X509verifycert() temporarily loads each caller-supplied untrusted intermediate into the certificate manager but failed to drop them before the trusted-store check, so an untrusted intermediate could anchor the path itself. An attacker can present a chain that never reaches a configured trust anchor and have it accepted, resulting in acceptance of an attacker-controlled certificate. This is certificate verification independent of TLS (e.g. S/MIME/CMS, code/firmware signing, JWT/JWS x5c), is not specific to any key type or algorithm, and a single untrusted intermediate suffices. The default wolfSSL TLS handshake (WOLFSSLVERIFYPEER) is not affected; only TLS applications doing manual or deferred peer verification through this API are, which also requires --enable-sessioncerts.

Integer Underflow Leads to Out-of-Bounds Access in XChaCha20-Poly1305 Decrypt

TLS 1.2 Client Can Downgrade Digest Used

Integer underflow in wolfSSL packet sniffer <= 5.8.4 allows an attacker to cause a buffer overflow in the AEAD decryption path by injecting a TLS record shorter than the explicit IV plus authentication tag into traffic inspected by sslDecodePacket. The underflow wraps a 16-bit length to a large value that is passed to AEAD decryption routines, causing heap buffer overflow and a crash. An unauthenticated attacker can trigger this remotely via malformed TLS Application Data records.

wolfSSL 5.8.4 on RISC-V RV32I architectures lacks a constant-time software implementation for 64-bit multiplication. The compiler-inserted muldi3 subroutine executes in variable time based on operand values. This affects multiple SP math functions (sp256mul9, sp256sqr9, etc.), leading to a timing side-channel that may expose sensitive cryptographic data.

In wolfSSL 5.8.4, constant-time masking logic in sp256getentry2569 is optimized into conditional branches (bnez) by GCC when targeting RISC-V RV32I with -O3. This transformation breaks the side-channel resistance of ECC scalar multiplication, potentially allowing a local attacker to recover secret keys via timing analysis.