---
id: CVE-2019-13628
aliases:
  - GHSA-q95h-vc86-hv77
  - PYSEC-2026-1066
title: wolfCrypt leaks cryptographic information via timing side channel
summary: wolfCrypt leaks cryptographic information via timing side channel
severity: medium
cvss: 4.7
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N'
vendor: wolfcrypt
product: wolfcrypt
ecosystem: pip
affected:
  - wolfcrypt < 4.1.0
patched:
  - wolfcrypt 4.1.0
published: '2022-05-24'
updated: '2026-07-07'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-q95h-vc86-hv77'
references:
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2019-13628'
  - url: 'https://eprint.iacr.org/2011/232.pdf'
  - url: 'https://github.com/wolfSSL/wolfcrypt-py'
  - url: 'https://minerva.crocs.fi.muni.cz'
  - url: 'https://tches.iacr.org/index.php/TCHES/article/view/7337'
  - url: 'http://www.openwall.com/lists/oss-security/2019/10/02/2'
tags:
  - osv
  - pip
epss: 0.00365
epssPercentile: 0.27543
ingestedAt: '2026-07-08T18:25:52.285Z'
---

## Overview

wolfSSL and wolfCrypt 4.0.0 and earlier (when configured without `--enable-fpecc`, `--enable-sp`, or` --enable-sp-math`) contain a timing side channel in ECDSA signature generation. This allows a local attacker, able to precisely measure the duration of signature operations, to infer information about the nonces used and potentially mount a lattice attack to recover the private key used. The issue occurs because ecc.c scalar multiplication might leak the bit length.

## Affected packages

- `wolfcrypt < 4.1.0`

## Remediation

Upgrade to a patched release:

- `wolfcrypt 4.1.0`