CVE-2025-48026: Mitel OpenScape Path Traversal Flaw

CVE-2025-48026 Overview

CVE-2025-48026 is a path traversal vulnerability in the WebApl component of Mitel OpenScape Xpressions through V7R1 FR5 HF43 P913. The flaw stems from insufficient input validation, allowing an unauthenticated remote attacker to read arbitrary files from the underlying operating system. Successful exploitation exposes sensitive configuration files, credentials, and other system data accessible to the web application process. The vulnerability is tracked under CWE-22: Improper Limitation of a Pathname to a Restricted Directory and is documented in Mitel Security Advisory MISA-2025-0005.

Critical Impact

Unauthenticated remote attackers can read arbitrary files from the host operating system, exposing sensitive information such as configuration files and credentials.

Affected Products

• Mitel OpenScape Xpressions through V7R1 FR5 HF43 P913
• WebApl component of OpenScape Xpressions
• Earlier OpenScape Xpressions V7R1 service packs and hotfixes

Discovery Timeline

• 2025-06-23 - CVE-2025-48026 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2025-48026

Vulnerability Analysis

The WebApl component of OpenScape Xpressions accepts user-supplied input that is used to construct file paths without adequate sanitization. An attacker can supply traversal sequences such as ../ to escape the intended directory and reference arbitrary files on the host. Because the endpoint is reachable without authentication, exploitation does not require credentials or user interaction. The attack targets confidentiality only, with no direct impact on integrity or availability based on the published vector.

Root Cause

The root cause is improper limitation of a pathname to a restricted directory [CWE-22]. The WebApl component fails to canonicalize or validate file path parameters before opening the requested resource. Input filtering does not strip or reject parent-directory references, allowing access outside the intended web root. Files readable by the service account running the web component become accessible to remote attackers.

Attack Vector

The attack vector is network-based and requires no authentication or user interaction. An attacker sends a crafted HTTP request to a vulnerable WebApl endpoint, supplying directory traversal sequences in a path or filename parameter. The server resolves the manipulated path and returns the contents of the targeted file. Typical targets include OS configuration files, application configuration containing credentials, and log files that may aid further compromise. Refer to the Mitel Security Advisory MISA-2025-0005 for vendor-specific technical detail.

Detection Methods for CVE-2025-48026

Indicators of Compromise

• HTTP requests to WebApl endpoints containing ../, ..\, encoded variants such as %2e%2e%2f, or absolute path references
• Web server access logs showing successful responses to requests referencing files outside the application directory
• Unusual reads of OS-level files such as /etc/passwd, win.ini, or Mitel configuration files by the web service process

Detection Strategies

• Inspect web server and reverse proxy logs for traversal patterns targeting the WebApl path
• Deploy signatures in web application firewalls and intrusion detection systems for path traversal payloads against OpenScape Xpressions URIs
• Correlate anomalous file-read activity by the OpenScape Xpressions service account with inbound HTTP requests

Monitoring Recommendations

• Forward OpenScape Xpressions web component logs to a centralized SIEM for retention and analysis
• Alert on response codes of 200 paired with request URIs containing traversal sequences
• Monitor outbound transfers of configuration or credential files from the OpenScape Xpressions host

How to Mitigate CVE-2025-48026

Immediate Actions Required

• Apply the fixes referenced in Mitel Security Advisory MISA-2025-0005 to all OpenScape Xpressions deployments
• Restrict network access to the WebApl interface to trusted management networks only
• Audit web server logs for prior exploitation attempts and rotate any credentials that may have been exposed

Patch Information

Mitel has published remediation guidance in MISA-2025-0005. Administrators should consult the advisory for the specific fixed version or hotfix applicable to their deployment of OpenScape Xpressions V7R1. Additional advisories are catalogued on the Mitel Security Advisories List.

Workarounds

• Place the WebApl interface behind a reverse proxy or web application firewall that blocks path traversal payloads
• Limit inbound access to the OpenScape Xpressions web component using network ACLs and firewall rules
• Reduce filesystem permissions of the service account running WebApl to limit the scope of readable files

# Example WAF rule concept to block traversal sequences targeting WebApl
# Reject requests containing ../ or encoded equivalents in the URI
SecRule REQUEST_URI "@rx (\.\./|\.\.\\|%2e%2e%2f|%2e%2e/|\.\.%2f)" \
    "id:1004826,phase:1,deny,status:403,msg:'Path traversal attempt against OpenScape Xpressions WebApl'"