Vulnerability · Published Jan 7, 2026 · Assigned by wolfSSL
CVE-2025-15346wolfSSL Python library `CERT_REQUIRED` mode fails to enforce client certificate requirement
Critical 9.3
In plain English
A critical-severity missing authentication in wolfSSL-py from wolfSSL. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 27% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | wolfssl | no fix listed | DEBIAN-CVE-2025-15346 |
| Debian:13 | wolfssl | no fix listed | DEBIAN-CVE-2025-15346 |
| Debian:14 | wolfssl | no fix listed | DEBIAN-CVE-2025-15346 |
| PyPI | wolfssl | 5.8.4.post0 | GHSA-vj87-jj27-4h9c |
| PyPI | wolfssl | 5.8.4.post0 | PYSEC-2026-575 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| wolfSSL | wolfSSL-py | 5.3.0 – through 5.8.2 |
Weakness: CWE-306, CWE-287 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/AU:Y