oqs-provider is a provider for the OpenSSL 3 cryptography library that adds support for post-quantum cryptography in TLS, X.509, and S/MIME using post-quantum algorithms from liboqs. Flaws have been identified in the way oqs-provider handles lengths decoded with DECODE_UINT32 at the start of serialized hybrid (traditional + post-quantum) keys and signatures. Unchecked length values are later used for memory reads and writes; malformed input can lead to crashes or information leakage. Handling of plain/non-hybrid PQ key operation is not affected. This issue has been patched in in v0.6.1. All users are advised to upgrade. There are no workarounds for this issue.
The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow.