MajorDoMo Supply Chain Remote Code Execution via Update URL Poisoning

published 2026-02-18 8 mo ago modified 2026-11-08 26 h ago also EUVD-2026-8370

cvss: 9.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 1.2%; EPSS 1.2% chance of exploitation in 30 days, percentile 68%
public exploits: 1; Metasploit

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.

Patch / fix

links 1

github.com/sergejey/majordomo#1177 pull request

Timeline

2026-02-18 First public exploit (Metasploit exploit/multi/http/majordomo_supply_chain_rce)
2026-02-18 Published

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: total
Assessed: 8 mo ago (2026-02-20)

Exploit prediction

1.20% chance of exploitation in the next 30 days, higher than 68% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

Metasploit exploit/multi/http/majordomo_supply_chain_rce MajorDoMo Supply Chain RCE via Update Poisoning metasploit exploit, excellent rank, 2026-02-18
github.com https://github.com/sergejey/majordomo/pull/1177 referenced PoC, tagged "exploit" by a source, unverified
chocapikk.com https://chocapikk.com/posts/2026/majordomo-revisited/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	9.3	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
CNA	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA	4.0	9.3	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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

sergejey MajorDoMo

Classification

Weakness

CWE-494 Download of Code Without Integrity Check

References

github.com /sergejey/majordomo/pull/1177
issue-tracking, patch, exploit
chocapikk.com /posts/2026/majordomo-revisited/
third-party-advisory, exploit
vulncheck.com /advisories/majordomo-supply-chain-remote-code-execution-via-update-url-poisoning
third-party-advisory

Sources

CVE List CVE-2026-27180
NVD CVE-2026-27180

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary