CVE-2026-104805: Mitel MiVoice Office 400 Backup Restoration Arbitrary File Write Leading to Root Code Execution

Vulnerability summary

CVE-2026-104805 is a high (CVSS 8.5) vulnerability in mitel mitel mivoice office 400. EPSS estimates a 0.22% chance of exploitation in the next 30 days, higher than 12% of scored vulnerabilities.

Timeline

1. 05-10-2026
   PublishedVulnerability first disclosed.
2. 05-10-2026
   Last modifiedVulnerability information updated.

Description

DigitalCanion has discovered a vulnerability in the backup restoration functionality that allows an attacker with access to the configured backup repository to introduce arbitrary files into the system during restoration. The specific flaw exists within the backup restoration mechanism, which fails to properly validate the paths, file types, integrity, and authenticity of files contained within a restored TGZ archive. The application does not perform file-signature verification before extracting the archive, allowing a specially crafted backup to contain attacker-controlled files. An attacker with access to the backup SFTP or other configured repository can therefore provide a malicious TGZ archive that, when restored by the system, may place arbitrary files on the underlying Linux system. Depending on the location and permissions of the extracted files, this behavior can potentially be leveraged to achieve arbitrary code execution with root privileges and compromise the underlying virtual machine. The absence of enforced backup passwords further reduces the protection provided by the backup mechanism and may facilitate unauthorized access to the repository.

• CWE-22Improper Limitation of a Pathname to a Restricted DirectoryThe product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
• CWE-73External Control of File Name or PathThe product allows user input to control or influence paths or file names that are used in filesystem operations.
• CWE-345Insufficient Verification of Data AuthenticityThe product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.
• CWE-434Unrestricted Upload of File with Dangerous TypeThe product allows the upload or transfer of dangerous file types that are automatically processed within its environment.
• CWE-494Download of Code Without Integrity CheckThe product downloads source code or an executable from a remote location and executes the code without sufficiently verifying the origin and integrity of the code.