CVE-2025-15346

CVE-2025-15346 is a critical-severity vulnerability with a CVSS 4.0 base score of 9.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-287.

Key facts

Description

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.

Frequently asked questions

What is CVE-2025-15346?
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.
How severe is CVE-2025-15346?
CVE-2025-15346 has a CVSS 4.0 base score of 9.3, rated critical severity.
Is CVE-2025-15346 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (19th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-15346?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2025-15346 have an EU (EUVD) identifier?
Yes. CVE-2025-15346 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-1463.
When was CVE-2025-15346 published?
CVE-2025-15346 was published on 2026-01-08 and last updated on 2026-06-17.

References

Other CWE-287 (Improper Authentication) vulnerabilities

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