CVE-2026-35079: Path Traversal Vulnerability in ugw-restore

CVE-2026-35079 Overview

CVE-2026-35079 is an arbitrary file deletion vulnerability in the ugw-restore method. The flaw stems from insufficient validation of user-controlled input, allowing a remote attacker with low-privileged user access to delete arbitrary local files on the affected system. The vulnerability is classified under [CWE-73] (External Control of File Name or Path).

Successful exploitation impacts the integrity and availability of the host. Attackers can remove configuration files, logs, or operational data, leading to service disruption or tampering with forensic evidence. The advisory was published by CERT-VDE on June 3, 2026.

Critical Impact
An authenticated remote attacker can delete arbitrary files on the host, causing service disruption and potential loss of critical configuration or log data.

Affected Products

Specific affected product details are referenced in the CERT-VDE Security Advisory. Consult the advisory for the authoritative list of impacted versions and components exposing the ugw-restore method.

Discovery Timeline

2026-06-03 - CVE CVE-2026-35079 published to NVD
2026-06-03 - Last updated in NVD database

Technical Details for CVE-2026-35079

Vulnerability Analysis

The ugw-restore method accepts user-controlled input that is used in file system operations without sufficient validation. An attacker authenticated as a low-privileged user can submit crafted parameters that reference file paths outside the intended restore scope.

Because the method performs deletion as part of the restore workflow, the resulting operation removes targeted files from the host. This breaks the integrity guarantees of the application and can render the device or service inoperable depending on the files targeted.

The attack vector is network-based and requires only low privileges. No user interaction is necessary, and the request can be issued through normal application channels exposed to authenticated users.

Root Cause

The root cause is improper validation of file path or file name parameters passed to the ugw-restore method. The implementation does not enforce a strict allow-list of permitted paths or canonicalize input to prevent traversal sequences. This aligns with [CWE-73], where externally supplied data influences a critical file path used in a privileged operation.

Attack Vector

An attacker first obtains low-privileged user credentials on the target system. The attacker then issues a request to the ugw-restore method with a manipulated file path parameter that references a sensitive file outside the restore directory. The backend executes the deletion using the attacker-supplied path, removing the targeted file. Repeated invocations can delete multiple files, escalating impact to denial of service or tampering with audit data. Detailed technical context is available in the CERT-VDE Security Advisory.

Detection Methods for CVE-2026-35079

Indicators of Compromise

Unexpected deletion of system files, configuration files, or log files coinciding with authenticated user sessions.
Application or service failures shortly after invocation of the ugw-restore method.
Authenticated API calls to ugw-restore containing path traversal sequences such as ../ or absolute paths outside the restore directory.

Detection Strategies

Inspect application logs for calls to ugw-restore and correlate parameters with file deletion events on the host.
Enable file integrity monitoring on critical directories to alert on unauthorized removal of files.
Audit authentication logs for low-privileged accounts performing restore operations outside expected maintenance windows.

Monitoring Recommendations

Centralize host and application logs to a SIEM and create alerts for ugw-restore invocations.
Track file deletion syscalls on the affected host, particularly when issued by the service account running the application.
Monitor for repeated 4xx or 5xx responses from the restore endpoint that may indicate exploitation attempts.

How to Mitigate CVE-2026-35079

Immediate Actions Required

Apply the vendor patch referenced in the CERT-VDE Security Advisory as soon as it is available.
Restrict network access to the management interface exposing the ugw-restore method to trusted administrative networks only.
Review and reduce the number of low-privileged accounts that can authenticate to the affected service.

Patch Information

Refer to the CERT-VDE Security Advisory VDE-2026-039 for authoritative patch and fixed-version information. Apply the vendor-supplied update on all affected systems and verify the fix by validating that the ugw-restore method rejects path traversal and absolute path inputs.

Workarounds

Disable the ugw-restore functionality if it is not required for normal operations.
Place the management interface behind a VPN or firewall rule that restricts access to authorized administrators.
Rotate credentials and enforce strong authentication for all accounts with access to the restore endpoint.

bash

# Configuration example: restrict access to the management interface
# Example iptables rule allowing only an administrative subnet
iptables -A INPUT -p tcp --dport 443 -s 10.0.10.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP