● Critical · CVSS 9.3

How to Fix CVE-2026-27180: Code Injection RCE in MajorDoMo

Q: Is CVE-2026-27180 being exploited in the wild?

Public exploitation has not been confirmed by CISA at the time of writing. Treat the patch as time-sensitive anyway; reports often lag actual abuse.

Q: Will a WAF or IDS rule fully mitigate CVE-2026-27180?

No. Network-layer filters can reduce noise and slow opportunistic scanners, but they will not stop a determined attacker. The vendor patch is the only durable fix.

Q: Do I need to assume compromise if my MajorDoMo was internet-facing and unpatched?

For an unauthenticated RCE-class flaw exposed to the public internet during the known exploitation window, yes. Review logs, rotate credentials the process could access, and look for unexpected accounts, scheduled tasks, or outbound connections.

Other vulnerabilities in the same area that are worth patching alongside this one:

How to Fix CVE-2026-22244: Server-Side Template Injection in OpenMetadata — Server-Side Template Injection in OpenMetadata
How to Fix CVE-2026-24923: Critical Vulnerability in HarmonyOS — Critical Vulnerability in HarmonyOS
How to Fix CVE-2026-3191: Minify HTML <= 2.1.12 - Cross-Site Request Forgery to Plugin Settings Update , Minify HTML <= 2.1.12 - Cross-Site Request Forgery to Plugin Settings Update
How to Fix CVE-2026-21004: CWE-287 Improper Authentication in Smart Switch , CWE-287 Improper Authentication in Smart Switch
How to Fix CVE-2026-7202: OS Command Injection in A8000RU , OS Command Injection in A8000RU

*By Sai Kiran Pandrala*

⚡ At a glance


Severity	CVSS 9.3 - Critical
Actively exploited?	Not currently listed in CISA KEV
Affected	0 <= *
Fixed in	URL
Type (CWE)	CWE-494: Download of Code Without Integrity Check

What is CVE-2026-27180?

CVE-2026-27180 is a code injection flaw in MajorDoMo. Attacker-controlled input is evaluated as code by the application runtime, giving the attacker arbitrary execution inside the process. Vendor 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.

Why this CVE matters

Code injection against an application server is a direct path to remote code execution. The attacker executes inside the application runtime, which means database credentials, integration keys, and any secrets the process has loaded in memory are all exposed.

For deployments of MajorDoMo that have been exposed to the public internet during the disclosure window, the operating assumption should be that scanning has already happened. Even where exploitation has not been publicly observed, scanning for the vulnerable fingerprint is cheap and routine. Patching closes the door; log review and credential rotation close out the rest of the response.

Am I affected?

You are affected if your installation matches any of these version ranges:

MajorDoMo: 0 <= *

Check your installed version against the list above. If you cannot determine the version, treat the system as affected and follow the upgrade path below.

Open MajorDoMo's About dialog or run the vendor-documented version-check command. Compare the result against the affected ranges in the advisory.

How to fix CVE-2026-27180

Read the vendor advisory in full: https://chocapikk.com/posts/2026/majordomo-revisited/
Upgrade MajorDoMo to the patched build listed in the vendor advisory.
Back up the configuration (and database, where applicable) before upgrading.
Rotate any credentials, API keys, or session tokens that the vulnerable service touched. An unauthenticated RCE-class flaw means anything the process could see should be treated as exposed.
Apply the patch in a maintenance window. For HA pairs, upgrade the standby node first, fail over, then upgrade the former primary.
Restart the affected service so the patched binary loads, then verify the new version (see verification section).

The commands below are runnable starting points. Adapt the package name, target version, and host paths to your environment using the vendor advisory linked under References.

npm / Yarn / pnpm


# Vendor advisory: https://chocapikk.com/posts/2026/majordomo-revisited/
# Update to the patched release named in the advisory
npm install majordomo@latest
# or pin to the exact fixed version from the vendor advisory
npm install majordomo@<patched-version>
npm ls majordomo

PyPI (pip / Poetry)


# Vendor advisory: https://chocapikk.com/posts/2026/majordomo-revisited/
pip install --upgrade majordomo
pip show majordomo | grep -i version
# Poetry:
poetry add majordomo@^<patched-version>

Docker / container


# Vendor advisory: https://chocapikk.com/posts/2026/majordomo-revisited/
docker pull <your-registry>/majordomo:<patched-tag>
docker stop <app> && docker rm <app>
docker run -d --name <app> <your-registry>/majordomo:<patched-tag>

PowerShell detect/upgrade/verify/log (Windows)


# CVE-2026-27180 remediation runner. Adapt version checks to your environment.
$log = "C:\Logs\CVE-2026-27180-fix.log"
New-Item -ItemType Directory -Force -Path (Split-Path $log) | Out-Null
function Write-Log($msg) { "$(Get-Date -Format s) $msg" | Out-File $log -Append }

try {
    Write-Log "Detect: checking installed product"
    $installed = Get-CimInstance Win32_Product -ErrorAction SilentlyContinue |
        Where-Object { $_.Name -match 'MajorDoMo' }
    if (-not $installed) { Write-Log "Product not installed; nothing to do"; return }
    Write-Log "Found version $($installed.Version)"

    Write-Log "Backup: copying program files and registry hive"
    $stamp = Get-Date -Format yyyyMMdd-HHmm
    $backup = "C:\Backup\CVE-2026-27180-$stamp"
    New-Item -ItemType Directory -Force -Path $backup | Out-Null
    Copy-Item $installed.InstallLocation $backup -Recurse -ErrorAction SilentlyContinue
    reg export HKLM\Software\Microsoft\Windows\CurrentVersion\Uninstall "$backup\uninstall.reg" /y | Out-Null

    Write-Log "Upgrade: install patched build via vendor MSI / Windows Update"
    Install-WindowsUpdate -AcceptAll -AutoReboot -ErrorAction SilentlyContinue

    Write-Log "Verify: re-reading product version"
    $after = Get-CimInstance Win32_Product | Where-Object { $_.Name -match 'MajorDoMo' }
    Write-Log "Post-patch version: $($after.Version)"
    if ($after.Version -ne $installed.Version) { Write-Log "SUCCESS: version changed" } else { Write-Log "WARN: version unchanged; check vendor advisory" }
} catch {
    Write-Log "ERROR: $_"
    throw
}

Bash detect/upgrade/verify/log (Linux)


#!/usr/bin/env bash
# CVE-2026-27180 remediation runner. Re-runnable, exits non-zero on failure.
set -euo pipefail
log() { printf '%s %s\n' "$(date -Is)" "$*" | tee -a /var/log/cve-2026-27180-fix.log; }

log "Detect: current majordomo version"
if command -v dpkg >/dev/null 2>&1; then
    current=$(dpkg-query -W -f='${Version}' majordomo 2>/dev/null || echo "not-installed")
elif command -v rpm >/dev/null 2>&1; then
    current=$(rpm -q --qf '%{VERSION}-%{RELEASE}' majordomo 2>/dev/null || echo "not-installed")
else
    current="unknown"
fi
log "Current: $current"

log "Backup: snapshotting config"
backup="/var/backups/cve-2026-27180-$(date +%Y%m%d-%H%M)"
mkdir -p "$backup"
[ -d /etc/majordomo ] && cp -a /etc/majordomo "$backup/" || true

log "Upgrade: applying vendor patch"
if command -v apt-get >/dev/null 2>&1; then
    sudo apt-get update -qq
    sudo apt-get install -y --only-upgrade majordomo
elif command -v dnf >/dev/null 2>&1; then
    sudo dnf upgrade -y majordomo
elif command -v yum >/dev/null 2>&1; then
    sudo yum update -y majordomo
fi

log "Verify: re-reading majordomo version"
if command -v dpkg >/dev/null 2>&1; then
    after=$(dpkg-query -W -f='${Version}' majordomo)
else
    after=$(rpm -q --qf '%{VERSION}-%{RELEASE}' majordomo)
fi
log "After: $after"

if [ "$after" != "$current" ]; then
    log "SUCCESS: majordomo upgraded"
else
    log "WARN: version unchanged. Confirm the patched build is in your repository."
    exit 1
fi

If you cannot patch immediately

No official workaround exists beyond restricting network exposure to the affected component. Apply the vendor patch as the primary remediation.

How to verify the fix worked

After applying the patch, verify the running version in the product's admin UI or via the vendor-documented CLI command.
Confirm the patched build matches the version listed in the vendor advisory.
Run an authenticated vulnerability scan with a current signature set and confirm the scanner no longer flags CVE-2026-27180.
Review logs for the entire pre-patch window for indicators of compromise listed in the vendor or CISA advisory.
Confirm any network-layer mitigations that were applied as a stopgap have been reverted (or left in place intentionally) once the patch is verified.

If your installation was internet-reachable during the disclosure window, treat log review as part of the remediation rather than an optional follow-up. Look for unexpected administrator accounts in MajorDoMo, scheduled tasks or cron jobs you did not create, new files in web-accessible directories, and outbound connections to addresses not in your baseline. Suspicious requests to the vulnerable endpoint immediately followed by successful 200-class responses with unusually large bodies are a strong indicator of exploitation.

Frequently asked questions

Is CVE-2026-27180 being exploited in the wild?