This vulnerability is a use-after-free condition in the handling of hybrid key-shares in PQC mode during a TLS 1.3 handshake. A malicious server that sends a truncated PQC hybrid KeyShare is able to cause the library’s cleanup path to operate on freed memory, which can lead to an application crash or, in the most severe case, memory corruption. The flaw is limited to the TLS handshake and does not provide an immediate path for remote code execution.

The defect exists in the wolfSSL library for all versions where the PQC hybrid key-share feature is enabled. No specific version release is listed, but the issue was noted as an incomplete-fix follow-up to a prior advisory, implying that earlier releases such as 5.9.1 may still be affected. Users of wolfSSL should check their installed version and apply any available patches.

The CVSS score of 2.3 rates this flaw as low severity. Because the exploitation requires a malicious TLS server that sends a malformed KeyShare, the attack vector is remote and constrained to TLS traffic. The EPSS score is currently unavailable, and the vulnerability is not in the CISA KEV catalog, indicating a low likelihood of widespread exploitation. Nonetheless, triggering a use-after-free can cause an application crash, potentially leading to denial of service.