CVE-2025-41250: VMware vCenter SMTP Injection Vulnerability

CVE-2025-41250 Overview

VMware vCenter contains an SMTP header injection vulnerability that allows malicious actors with non-administrative privileges to manipulate notification emails sent for scheduled tasks. This command injection vulnerability (CWE-77) enables attackers who have permission to create scheduled tasks to inject arbitrary SMTP headers, potentially leading to email spoofing, phishing campaigns, or information disclosure through manipulated email routing.

Critical Impact

Attackers with low-privilege access to vCenter can exploit this SMTP header injection to manipulate email notifications, potentially enabling phishing attacks against administrators or exfiltrating sensitive information through modified email headers.

Affected Products

• VMware vCenter Server (specific versions to be confirmed in vendor advisory)

Discovery Timeline

• 2025-09-29 - CVE-2025-41250 published to NVD
• 2025-09-29 - Last updated in NVD database

Technical Details for CVE-2025-41250

Vulnerability Analysis

This SMTP header injection vulnerability exists in VMware vCenter's scheduled task notification system. The flaw stems from improper sanitization of user-controlled input when constructing email headers for task notifications. When a user with scheduled task creation privileges submits specially crafted input, the application fails to properly validate and escape SMTP header delimiters (CRLF sequences), allowing arbitrary headers to be injected into outgoing notification emails.

The vulnerability's scope extends beyond the vulnerable component, meaning successful exploitation can affect resources managed by different security authorities. While confidentiality is not directly impacted, the integrity impact is significant as attackers can manipulate email content and routing. Additionally, there is a low availability impact on the email notification system.

Root Cause

The root cause of CVE-2025-41250 is improper input validation (CWE-77: Command Injection) in the email notification subsystem of VMware vCenter. The application fails to sanitize carriage return (\r) and line feed (\n) characters in user-supplied data before incorporating it into SMTP headers. This allows attackers to terminate existing headers and inject new ones, breaking the expected structure of the email message.

Attack Vector

The attack is network-accessible and requires low privileges—specifically, the ability to create scheduled tasks in vCenter. No user interaction is required for exploitation. An attacker would:

1. Authenticate to VMware vCenter with a low-privilege account that has scheduled task creation permissions
2. Create a scheduled task with maliciously crafted input containing CRLF sequences followed by arbitrary SMTP headers
3. When the task triggers a notification, the injected headers are included in the outgoing email

This could be leveraged to add BCC recipients for data exfiltration, modify the From header for spoofing attacks, inject additional content into the email body, or redirect emails to attacker-controlled servers.

Detection Methods for CVE-2025-41250

Indicators of Compromise

• Unusual SMTP traffic patterns originating from vCenter servers
• Email notifications containing unexpected headers or recipients
• Scheduled tasks with suspicious characters in name or description fields (particularly \r\n sequences or encoded variants)
• Mail server logs showing emails from vCenter with anomalous header structures

Detection Strategies

• Monitor vCenter audit logs for scheduled task creation events from unusual accounts or containing suspicious input patterns
• Implement email gateway rules to flag or quarantine vCenter notifications with unexpected header configurations
• Deploy network monitoring to detect SMTP traffic from vCenter to unauthorized mail servers
• Review vCenter scheduled tasks for entries containing URL-encoded or raw CRLF sequences

Monitoring Recommendations

• Enable detailed logging for scheduled task operations in VMware vCenter
• Configure SIEM alerts for email header anomalies in vCenter notification traffic
• Implement regular audits of scheduled tasks and their configurations across all vCenter instances
• Monitor for privilege escalation attempts that could grant scheduled task creation permissions to unauthorized users

How to Mitigate CVE-2025-41250

Immediate Actions Required

• Review and restrict permissions for scheduled task creation to only trusted administrative accounts
• Audit existing scheduled tasks for suspicious content or unexpected configurations
• Implement network segmentation to limit vCenter's SMTP connectivity to authorized mail servers only
• Apply the vendor security patch as soon as it becomes available from Broadcom

Patch Information

Broadcom has released a security advisory addressing this vulnerability. Administrators should consult the Broadcom Security Advisory for specific patch versions and update instructions. Apply the recommended patches to all affected VMware vCenter Server instances following your organization's change management procedures.

Workarounds

• Restrict scheduled task creation privileges to only essential administrative accounts until patches can be applied
• Implement email gateway filtering to validate header integrity on all emails originating from vCenter servers
• Consider temporarily disabling email notifications for scheduled tasks if not operationally critical
• Deploy network-level controls to monitor and restrict SMTP traffic from vCenter infrastructure

Consult the Broadcom Security Advisory for official workaround guidance and additional mitigation recommendations.