---
title: "CVE-2025-15346: wolfSSL Python module vulnerable to Improper Authentication"
url: https://erroneo.us/security/cve/CVE-2025-15346/
description: "CVE-2025-15346 (wolfssl (PyPI)): A vulnerability in the handling of verifymode = CERTREQUIRED in the wolfssl Python package (wolfssl-py) causes client…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-01-07
date_modified: 2026-01-30
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2025-15346"
kev: false
cvss: 9.3
epss: 0.00334
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2025-15346: wolfSSL Python module vulnerable to Improper Authentication

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.3% , percentile 26: FIRST’s model estimates a 0.3% chance of exploitation activity in the next 30 days, higher than 26% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes wolfssl (PyPI) < 5.8.4.post0, fixed in 5.8.4.post0 . Check your lockfile, including transitive dependencies.

## What it is

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. 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

- PyPI `wolfssl` < 5.8.4.post0 → fixed: 5.8.4.post0

## Affected products (CVE record)

- wolfSSL wolfSSL-py: 5.3.0 <= 5.8.2

## Severity

- wolfSSL CVSS 4.0: 9.3 `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`
- GitHub CVSS 4.0: 9.3 `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`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.33% probability of exploitation activity in the next 30 days; percentile 26.

## Sources

- [GitHub Advisory GHSA-vj87-jj27-4h9c](https://github.com/advisories/GHSA-vj87-jj27-4h9c)
- [CVE.org record CVE-2025-15346](https://www.cve.org/CVERecord?id=CVE-2025-15346)
- [NVD entry CVE-2025-15346](https://nvd.nist.gov/vuln/detail/CVE-2025-15346)
- [github.com](https://github.com/wolfSSL/wolfssl-py/pull/62)
- [github.com](https://github.com/wolfSSL/wolfssl-py/commit/b4517dece79f682a8f453abce5cfc0b81bae769d)
- [github.com](https://github.com/wolfSSL/wolfssl-py/releases/tag/v5.8.4-stable)

---
Source page: https://erroneo.us/security/cve/CVE-2025-15346/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt