TI-2025-13999 Aliases CVE-2025-15346 GHSA-vj87-jj27-4h9c

wolfSSL Python library `CERT_REQUIRED` mode fails to enforce client certificate requirement

MEDIUM 48CWE-287Published 2026-01-07 · Updated 2026-01-08

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Attack requirements: None
Impact type: Security bypass
Confidentiality · integrity · availability: High · High · None
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-287.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00334 26th percentileScored 2026-11-07

Fix Fixed wolfssl (PyPI): 5.8.4.post0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: Yes
Technical impact: Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
wolfSSL	wolfSSL-py	5.3.0 – 5.8.2	—	No fix listed	CNA
—	wolfssl (PyPI)	before 5.8.4.post0	5.8.4.post0	Patch available	GHSA-vj87-jj27-4h9c

wolfSSL-py VendorwolfSSL Affected 5.3.0 – 5.8.2 Fixed in — No fix listed CNA
wolfssl (PyPI) Vendor— Affected before 5.8.4.post0 Fixed in 5.8.4.post0 Patch available GHSA-vj87-jj27-4h9c

Remediation

Fix · GHSA-vj87-jj27-4h9c wolfssl (PyPI) Fixed in 5.8.4.post0 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2025-15346
2026-10-03 Alias added: GHSA-vj87-jj27-4h9c

References

Advisory 1

https://nvd.nist.gov/vuln/detail/CVE-2025-15346

Other 4

TI-2024-00830 SEGV and out of bounds memory read from malicious packet CVSS 3.1CRITICAL 9.1
TI-2009-04246 Multiple stack-based buffer overflows in the CertDecoder::GetName function in src/asn.cpp… CVSS 2.0HIGH 7.5
TI-2022-18557 In wolfSSL before 5.5.1, malicious clients can cause a buffer overflow during a TLS 1.3… CVSS 3.1HIGH 7.5
TI-2025-10943 Potential DoS Vulnerability through Multiple KeyShareEntry with Same Group in TLS 1.3 ClientHello CVSS 4.0MEDIUM 6.3
TI-2017-09737 wolfSSL Bleichenbacher/ROBOT CVSS 3.0HIGH 7.5
TI-2019-08902 wolfSSL 4.0.0 has a Buffer Overflow in DoPreSharedKeys in tls13.c when a current identity… CVSS 3.1CRITICAL 9.8

See all 176 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences