CVE-2026-114425 in Secure Email Gateway
Summary
by MITRE • 11/04/2026
SEPPmail Secure Email Gateway before 15.1.1 trusts a file path supplied in externally provided Large File Transfer attachment metadata. An unauthenticated remote sender can cause the mail-processing worker to disclose, move, or delete an accessible regular file when LFT is enabled and the message reaches an affected secure-mail processing path. The validated workers ran as root.
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Analysis
by VulDB Data Team • 11/04/2026
The vulnerability identified in SEPPmail Secure Email Gateway prior to version 15.1.1 represents a critical security flaw rooted in improper input validation of external data, specifically within the metadata associated with Large File Transfer attachments. This issue falls under the category of Path Traversal or Unrestricted Upload of File with Dangerous Type, often mapped to CWE-22 and CWE-434 respectively in standard vulnerability classification systems. The core technical failure lies in the application's trust model regarding file paths provided by unauthenticated remote senders. When a message containing such an attachment enters the processing pipeline enabled for Large File Transfer functionality, the system fails to adequately sanitize or validate the path information embedded within the attachment metadata before using it in subsequent file operations.
This lack of validation allows an attacker to manipulate the internal logic of the mail-processing worker by supplying maliciously crafted paths that reference locations outside the intended directory structure. By exploiting this weakness, a remote adversary can influence which files are accessed or modified on the underlying operating system. The operational impact is severe because the vulnerability enables actions such as disclosing sensitive information from accessible regular files, moving critical system or application files to unintended locations, or deleting essential data entirely. This capability effectively grants an unauthenticated user significant control over file system integrity and confidentiality, potentially leading to complete compromise of the email gateway's security posture.
The severity of this flaw is significantly amplified by the execution context in which the vulnerable components operate. The validated workers responsible for processing these messages run with root privileges. Consequently, any successful exploitation does not merely affect a sandboxed or restricted user environment but directly impacts the host system at its highest level of authority. This means that an attacker can read sensitive configuration files, intercept cryptographic keys stored on disk, overwrite executable binaries to establish persistence, or delete logs and audit trails to cover their tracks. The combination of path traversal logic with elevated privileges creates a high-severity risk vector that aligns closely with ATT&CK techniques related to Command and Scripting Interpreter abuse as well as File and Directory Permissions Modification.
Mitigation strategies must prioritize immediate patching to version 15.1.1 or later, where the input validation mechanisms have been corrected to strictly enforce allowed characters and canonicalize paths before processing. In addition to software updates, organizations should implement defense-in-depth measures such as running mail-processing services with least-privilege principles rather than root access, utilizing chroot jails or containers to isolate file system interactions, and deploying intrusion detection systems capable of identifying anomalous file path patterns in email headers and attachments. Regular auditing of large file transfer configurations and strict validation of all external inputs are essential practices to prevent similar exploitation vectors from being leveraged against the infrastructure.