Technical impact
The flaw in the wolfSSL library allows a client to accept any certificate in the presented chain as a trusted issuer, bypassing normal CA validation. When OCSP stapling v2 is enabled, an attacker who possesses a certificate that chains to a CA trusted by the client—and its private key—can create forged certificates for arbitrary identities. These forged certificates are then considered valid by the client, enabling impersonation or man‑in‑the‑middle attacks. The vulnerability stems from improper certificate chain verification and is identified as CWE‑295.
Affected Systems
wolfSSL library, versions 5.7.2 through 5.9.2, used when a client enables the HAVE_CERTIFICATE_STATUS_REQUEST_V2 feature and calls wolfSSL_UseOCSPStaplingV2 with the WOLFSSL_CSR2_OCSP_MULTI option.
Risk and Exploitability
The CVSS score of 8.3 designates high severity. The EPSS score is not available, indicating no data on current exploitation likelihood, though the vulnerability is not listed in the CISA KEV catalog. Attackers must target a wolfSSL‑based client that has OCSP stapling v2 enabled; a compromised certificate issuer can then sign forged server certificates that the client will accept. The exploit is client‑side, requiring the attacker to control a TLS client application or supply a trusted certificate chain. While no public exploits have been observed, the high impact warrants timely mitigation.
