XSS in Mjdm Majordomo
CVE-2026-27178
MajorDoMo (aka Major Domestic Module) contains a stored cross-site scripting (XSS) vulnerability through method parameter injection into the shoutbox. The /objects/?method= endpoint allows unauthenticated execution of stored methods with attacker-controlled parameters. Default methods such as ThisComputer.VolumeLevelChanged pass the user-supplied VALUE parameter directly into the say() function, which stores the message raw in the shouts database table without escaping. The shoutbox widget renders stored messages without sanitization in both PHP rendering code and HTML templates. Because the dashboard widget auto-refreshes every 3 seconds, the injected script executes automatically when any administrator loads the dashboard, enabling session hijack through cookie exfiltration.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.004 (32.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 32nd percentile — 32.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.004 · change: +0.002
Affected products
- Mjdm Majordomo
- Sergejey Majordomo — versions 0
Weakness classification (CWE)
References
- chocapikk.com/posts/2026/majordomo-revisited/ (Exploit, Third Party Advisory, third-party-advisory)
- github.com/sergejey/majordomo/pull/1177 (issue-tracking, Exploit, patch, Issue Tracking)
- www.vulncheck.com/advisories/majordomo-stored-cross-site-scripting-via-method-p… (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-27178?
- CVE-2026-27178 is a high-severity vulnerability in Mjdm Majordomo, classified under Cross-site Scripting. CVSS score: 7.2/10. Published 2026-02-18.
- How severe is CVE-2026-27178?
- High severity. CVSS v3 base score is 7.2 out of 10.