Openfind MailGates/MailAudit Stack-based Buffer Overflow (CVE-2026-6350)

Openfind MailGates and MailAudit are susceptible to a critical stack-based buffer overflow vulnerability, identified as CVE-2026-6350. This flaw allows unauthenticated remote attackers to gain control over the program’s execution flow and execute arbitrary code on the affected system. The vulnerability stems from insufficient input validation, leading to a buffer overflow when processing specifically crafted requests. Given the nature of MailGates/MailAudit as email security solutions, successful exploitation can lead to a full compromise of the email infrastructure and potential data breaches. The vulnerability was reported on April 15, 2026, and affects undisclosed versions of MailGates/MailAudit.

Attack Chain

1. An unauthenticated remote attacker identifies a vulnerable MailGates/MailAudit instance.
2. The attacker crafts a malicious network request specifically designed to trigger the stack-based buffer overflow in MailGates/MailAudit.
3. The attacker sends the crafted request to the targeted MailGates/MailAudit server.
4. The vulnerable application receives and processes the malicious request without proper input sanitization.
5. The oversized input overwrites adjacent memory on the stack, including the return address.
6. When the function attempts to return, it jumps to an address controlled by the attacker.
7. The attacker-controlled address points to shellcode injected within the overflowing buffer or elsewhere in memory.
8. The shellcode executes arbitrary commands on the server, potentially leading to complete system compromise and data exfiltration.

Impact

Successful exploitation of CVE-2026-6350 allows unauthenticated remote attackers to execute arbitrary code on the MailGates/MailAudit server. This can result in full system compromise, allowing attackers to steal sensitive email data, modify email content, or use the compromised server as a launchpad for further attacks. Given that MailGates/MailAudit are used by numerous organizations for email security, a successful widespread attack could impact potentially thousands of organizations and millions of users.

Recommendation

• Monitor web server logs for unusual request patterns indicative of buffer overflow attempts targeting MailGates/MailAudit.
• Inspect network traffic for suspicious payloads being sent to MailGates/MailAudit servers, looking for patterns that could indicate exploit attempts.
• Deploy the Sigma rule provided below to detect potential exploitation attempts targeting CVE-2026-6350.
• Consult Openfind’s security advisories for patches and mitigation steps specific to CVE-2026-6350.
• If available apply updates provided by Openfind to remediate CVE-2026-6350 on the MailGates/MailAudit servers.