CVE-2026-8431: MongoDB Ops Manager RCE Vulnerability

CVE-2026-8431 Overview

CVE-2026-8431 is a command injection vulnerability in MongoDB Ops Manager affecting webhook configuration functionality. An administrative user with permission to configure webhooks can supply specific FreeMarker template syntax that executes arbitrary commands when the webhook is triggered. The flaw is tracked under CWE-77: Improper Neutralization of Special Elements used in a Command. The issue affects all MongoDB Ops Manager 7.0 versions and MongoDB Ops Manager 8.0.22 and earlier. MongoDB addressed the vulnerability in Ops Manager 8.0.23.

Critical Impact
Authenticated administrative attackers can achieve arbitrary command execution on the Ops Manager host through malicious FreeMarker template payloads in webhook configurations.

Affected Products

MongoDB Ops Manager 7.0 (all versions)
MongoDB Ops Manager 8.0.22 and prior
MongoDB Ops Manager webhook configuration component

Discovery Timeline

2026-05-12 - CVE-2026-8431 published to NVD
2026-05-13 - Last updated in NVD database

Technical Details for CVE-2026-8431

Vulnerability Analysis

MongoDB Ops Manager allows administrators to configure webhooks that fire on monitoring and alerting events. The webhook subsystem processes administrator-supplied content through the Apache FreeMarker template engine. FreeMarker exposes built-in functions and object reflection capabilities that can reach Java runtime methods when templates are not executed in a restricted sandbox.

An administrator with webhook configuration privileges can embed FreeMarker directives that resolve to freemarker.template.utility.Execute or equivalent reflection chains. When the webhook is triggered, the template engine evaluates the payload server-side and runs the embedded operating system commands under the privileges of the Ops Manager process.

Root Cause

The root cause is improper neutralization of FreeMarker template syntax in webhook fields [CWE-77]. The application treats privileged user input as trusted template content and renders it without sandboxing the engine or stripping dangerous built-ins. This trust boundary error converts a configuration interface into a command execution primitive.

Attack Vector

Exploitation requires network access to the Ops Manager web interface and an authenticated account with high privileges, specifically webhook configuration rights. The attacker creates or modifies a webhook, embedding crafted FreeMarker syntax into a templated field. Triggering the webhook through an alert or test action causes the server to evaluate the template and execute the embedded commands. The scope changes because injected commands run with the Ops Manager service account, which typically holds broad access to fleet configuration and credentials.

No verified public proof-of-concept code is available. Refer to the MongoDB Ops Manager 8.0.23 Release Notes for vendor technical details.

Detection Methods for CVE-2026-8431

Indicators of Compromise

Webhook configuration entries containing FreeMarker directives such as <#assign>, ?new(), freemarker.template.utility.Execute, or Runtime.getRuntime().
Unexpected child processes spawned by the Ops Manager Java process, including shells, curl, wget, or scripting interpreters.
Outbound network connections from the Ops Manager host to unfamiliar destinations following webhook trigger events.
Audit log entries showing webhook create, update, or test operations from unusual administrative accounts or source addresses.

Detection Strategies

Inspect Ops Manager audit logs for webhook configuration changes and correlate them with process execution telemetry on the host.
Hunt for FreeMarker reflection patterns in webhook payload fields stored in the Ops Manager application database.
Alert on Java process trees where the Ops Manager service spawns command interpreters such as /bin/sh, /bin/bash, cmd.exe, or powershell.exe.

Monitoring Recommendations

Forward Ops Manager application and audit logs to a centralized analytics platform for retention and correlation.
Enable host-based process and network telemetry on all Ops Manager servers and baseline expected behavior.
Review administrator account activity and enforce alerting on webhook configuration changes outside approved change windows.

How to Mitigate CVE-2026-8431

Immediate Actions Required

Upgrade MongoDB Ops Manager to version 8.0.23 or later as the primary remediation.
Audit all existing webhook configurations and remove any entries containing FreeMarker directives or unexpected template syntax.
Restrict administrative roles with webhook configuration privileges to the minimum required personnel and rotate credentials for any accounts suspected of misuse.

Patch Information

MongoDB resolved the vulnerability in Ops Manager 8.0.23. Customers running 7.0.x and 8.0.22 or earlier should plan an immediate upgrade. See the MongoDB Ops Manager 8.0.23 Release Notes for upgrade guidance.

Workarounds

Limit network access to the Ops Manager administrative interface to trusted management networks only.
Enforce multi-factor authentication on all administrative accounts and review the role assignments that grant webhook configuration rights.
Disable or remove webhook integrations that are not actively required until the patched version is deployed.

bash

# Verify the running Ops Manager version before and after upgrade
curl -u "<admin>:<api-key>" \
  https://<ops-manager-host>/api/public/v1.0/unauth/version