CVE-2026-125393
Received Received - Intake

Heap Overflow in MailEnable Enterprise Premium

Publication date: 2026-11-10

Last updated on: 2026-11-10

Assigner: VulnCheck

Description
MailEnable Enterprise Premium before 10.62 contains a heap overflow vulnerability in the IMAP X-FB-FETCH command that allows authenticated users to overflow a fixed 0x400-byte heap buffer. Attackers can supply an X-FB-USER address longer than about 1016 bytes, which is formatted without a length check, to crash the IMAP service and cause denial of service.

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Meta Information

Published
2026-11-10
Last Modified
2026-11-10
Generated
2026-11-10
AI Q&A
2026-11-10
EPSS Evaluated
N/A
NVD
CVE-2026-125393
EUVD
EUVD-2026-120556

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
MailEnable MailEnable Enterprise Premium From 0 (inc) to 10.62 (exc)

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-122 A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

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Executive Summary

MailEnable Enterprise Premium before version 10.62 has a heap overflow vulnerability in the IMAP X-FB-FETCH command. Authenticated users can send an X-FB-USER address longer than 1016 bytes, which overflows a fixed 0x400-byte heap buffer. This causes the IMAP service to crash, leading to denial of service.

Detection Guidance

Monitor IMAP service crashes or unusual traffic patterns. Check MailEnable logs for IMAP X-FB-FETCH command errors. Use network monitoring tools to detect excessive data sent to IMAP ports (default 143 or 993).

Commands: 'telnet localhost 143', 'openssl s_client -connect localhost:993' to test IMAP connectivity. Inspect logs in MailEnable's installation directory for heap overflow errors.

Impact Analysis

This vulnerability allows attackers with authenticated access to crash the IMAP service, causing downtime and disrupting email services. It does not directly enable data theft or code execution but can severely impact availability.

Compliance Impact

This vulnerability primarily causes denial of service by crashing the IMAP service, which could disrupt email availability. While not directly exposing data, prolonged outages may impact compliance with GDPR's availability principle or HIPAA's access requirements. The lack of service availability could also hinder incident response obligations under these regulations.

Mitigation Strategies

Upgrade MailEnable Enterprise Premium to version 10.62 or later immediately. Disable IMAP X-FB-FETCH command if not required. Restrict IMAP access to trusted networks only.

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