CVE-2026-5460: wolfSSL

Medium severity, CVSS 6.5. EPSS: 0.3% chance of exploitation in the next 30 days.

A heap use-after-free exists in wolfSSL's TLS 1.3 post-quantum cryptography (PQC) hybrid KeyShare processing. In the error handling path of TLSX_KeyShare_ProcessPqcHybridClient() in src/tls.c, the inner function TLSX_KeyShare_ProcessPqcClient_ex() frees a KyberKey object upon encountering an error. The caller then invokes TLSX_KeyShare_FreeAll(), which attempts to call ForceZero() on the already-freed KyberKey, resulting in writes of zero bytes over freed heap memory.

Affected products

• wolfSSL wolfSSL: before 5.9.1 (fixed in 5.9.1)

Published 2026-04-10. Last modified 2026-06-17.