CVE-2024-11182: MDaemon Email Server Cross-Site Scripting (XSS) Vulnerability

What it is

An XSS issue was discovered in MDaemon Email Server before version 24.5.1c. An attacker can send an HTML e-mail message with JavaScript in an img tag. This could allow a remote attacker to load arbitrary JavaScript code in the context of a webmail user's browser window.

Exploitation evidence

First exploit evidence seen: 2025-05-19 (earliest date across the sources below).

Exploited in the wild

• CISA KEV: listed since 2025-05-19. Source

Sources: CISA KEV.

How to fix it

CISA required action

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. (source: CISA KEV)

Fixed versions

• mdaemon mdaemon: upgrade to 24.5.1 or later

Derived from the NVD CPE configuration (versionEndExcluding / versionEndIncluding). Always confirm with the vendor advisory.

Vendor advisories and patches

• https://files.mdaemon.com/mdaemon/beta/RelNotes_en.html (CISA KEV notes)
• https://mdaemon.com/pages/downloads-critical-updates (CISA KEV notes)

MITRE ATT&CK mitigations for this chain

• M1047 Audit (for T1566, T1059) : Perform audits or scans of systems, permissions, insecure software, insecure configurations, etc. to identify potential weaknesses.
• M1031 Network Intrusion Prevention (for T1566) : Network intrusion prevention systems and systems designed to scan and remove malicious email attachments or links can be used to block activity.
• M1054 Software Configuration (for T1566) : Use anti-spoofing and email authentication mechanisms to filter messages based on validity checks of the sender domain (using SPF) and integrity of messages (using DKIM). Enabling these mechanisms within an organization (through policies such as DMARC) may enable recipients (intra-org and cross domain) to perform simil
• M1021 Restrict Web-Based Content (for T1566, T1059, T1567) : Determine if certain websites or attachment types (ex: .scr, .exe, .pif, .cpl, etc.) that can be used for phishing are necessary for business operations and consider blocking access if activity cannot be monitored well or if it poses a significant risk.
• M1049 Antivirus/Antimalware (for T1566, T1059) : Anti-virus can automatically quarantine suspicious files.
• M1017 User Training (for T1566) : Users can be trained to identify social engineering techniques and phishing emails.
• M1033 Limit Software Installation (for T1059) : Prevent user installation of unrequired command and scripting interpreters.
• M1045 Code Signing (for T1059) : Where possible, only permit execution of signed scripts.
• M1042 Disable or Remove Feature or Program (for T1059) : Disable or remove any unnecessary or unused shells or interpreters.
• M1038 Execution Prevention (for T1059) : Use application control where appropriate. For example, PowerShell Constrained Language mode can be used to restrict access to sensitive or otherwise dangerous language elements such as those used to execute arbitrary Windows APIs or files (e.g., `Add-Type`).

Detection Generic guidance

• Initial Access: Alert on unusual requests to the affected service (odd paths, oversized payloads, exploit strings) in WAF, reverse-proxy and application logs.
• Execution: Watch for the service process spawning shells or script interpreters (cmd.exe, powershell, sh, bash, python) via EDR process-tree rules.
• Exfiltration: Watch for large or unusual outbound transfers from the affected host.

Response checklist Generic guidance

1. Inventory: find every instance of the affected product and version (include internet-facing and forgotten ones).
2. Patch or mitigate per the vendor advisory; if you cannot patch, remove internet exposure or apply the vendor workaround.
3. Assume compromise if the system was exposed before patching: hunt for the indicators in the advisory and review logs back to the disclosure date.
4. Rotate credentials and secrets stored on or used by the affected system if compromise cannot be ruled out.