CVE-2025-15346: wolfSSL Python module vulnerable to Improper Authentication
A vulnerability in the handling of verifymode = CERTREQUIRED in the wolfssl Python package (wolfssl-py) causes client certificate requirements to not be fully enforced. Because the WOLFSSLVERIFYFAILIFNOPEERCERT flag was not included, the behavior effectively matched CERTOPTIONAL: a peer certificate was verified if presented, but connections were incorrectly authenticated when no client certificate was provided.
Published Jan 8, 2026 · Updated Jan 30, 2026
Affected packages
wolfssl
- Ecosystem
- PyPI
- Affected
- < 5.8.4.post0
- Fixed in
- 5.8.4.post0
- Check
pip show wolfssl
Advisory details
From the GitHub Advisory Database (CC BY 4.0).
A vulnerability in the handling of verify_mode = CERT_REQUIRED in the wolfssl Python package (wolfssl-py) causes client certificate requirements to not be fully enforced.
Because the WOLFSSL_VERIFY_FAIL_IF_NO_PEER_CERT flag was not included, the behavior effectively matched CERT_OPTIONAL: a peer certificate was verified if presented, but connections were incorrectly authenticated when no client certificate was provided.
This results in improper authentication, allowing attackers to bypass mutual TLS (mTLS) client authentication by omitting a client certificate during the TLS handshake.
The issue affects versions up to and including 5.8.2.
Credited to rhdesmond.
References
How this page is made: the data panel comes from the GitHub Advisory Database, CISA’s KEV catalog, the NVD and FIRST EPSS, and updates twice a day. No analysis has been written for this entry yet. Methodology