What’s Vulnerable › Vulnerabilities
CVE-2026-5460: Heap Use-After-Free in PQC Hybrid KeyShare Error Cleanup in wolfSSL TLS 1.3
- Severity: medium (CVSS 6.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.2% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-04-10 · updated 2026-06-17
- Weakness: CWE-416
Description
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: before 5.9.1 — fixed in 5.9.1
How to fix
Upgrade to a fixed version: wolfSSL 5.9.1. Check the vendor advisory for mitigations.
References
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