The vulnerability resides in the X.509 certificate chain verification routine of openHiTLS. The library only checks the basic constraints extension and CA flag for v3 certificates; v1 or v2 certificates in intermediate positions are ignored, which allows an attacker to insert a forged intermediate that bypasses the CA validation. This flaw can enable the acceptance of self‑signed or malicious certificates in place of legitimate ones, compromising the integrity of TLS handshakes. The weakness is an improper validation check (CWE‑295).

The affected product is the openHiTLS TLS library, and versions from 0.2.0 through 0.3.2 contain the flaw. Systems that link against these library versions rely on openHiTLS for TLS protocol operation, so they expose the certificate validation logic to the described weakness.

Based on the description, it is inferred that an attacker could supply a custom certificate chain that contains a v1 or v2 intermediate, thereby bypassing validation and accepting a forged chain. The likely attack vector is a man‑in‑the‑middle or spoofed certificate scenario where the verifier accepts the forged chain. The CVSS score of 6.8 indicates a moderate severity, while the EPSS score of <1% suggests a low exploitation probability. The vulnerability is not listed in the CISA KEV catalog at present.