CVE-2026-35077: Path Traversal Vulnerability Explained

CVE-2026-35077 Overview

CVE-2026-35077 is an arbitrary file deletion vulnerability in the ugw-delete-file method. The method fails to validate user-controlled input before performing file system operations. A remote attacker with low-privileged user credentials can delete arbitrary local files on the affected system. The flaw is categorized under [CWE-73] External Control of File Name or Path. Successful exploitation can corrupt configuration data, disrupt service availability, and impact system integrity. The vulnerability was published through a CERT-VDE security advisory, indicating an industrial or operational technology product context.

Critical Impact
Authenticated remote attackers can delete arbitrary files on the target system, leading to integrity loss and denial of service on critical processes.

Affected Products

Product details are referenced in the CERT-VDE advisory VDE-2026-039
Specific vendor and product names were not populated in the NVD record at publication time
Refer to the vendor advisory for the complete list of impacted versions

Discovery Timeline

2026-06-03 - CVE-2026-35077 published to NVD
2026-06-03 - Last updated in NVD database

Technical Details for CVE-2026-35077

Vulnerability Analysis

The vulnerability resides in the ugw-delete-file method exposed by the affected product. The method accepts a file path parameter from authenticated callers and passes it directly to a file deletion routine. Insufficient validation of this user-controlled input allows path manipulation. An attacker can supply absolute paths or directory traversal sequences to target files outside the intended directory scope.

Because the operation executes with the privileges of the underlying service account, the attacker can remove files that the service has permission to delete. Targets typically include configuration files, log files, database artifacts, and binaries required for normal operation. Removing such files damages system integrity and can cause the application to crash or refuse to start.

Root Cause

The root cause is improper input validation [CWE-73]. The ugw-delete-file handler does not enforce a canonical base directory, does not normalize the supplied path, and does not reject traversal sequences such as ../. The method also treats any authenticated user as authorized to invoke destructive file operations, which violates least-privilege principles.

Attack Vector

Exploitation requires network access to the management interface and valid low-privileged credentials. The attacker authenticates, then issues a crafted request to the ugw-delete-file method with a path pointing to a sensitive file. No user interaction is required. The CERT-VDE advisory linked above provides the authoritative technical breakdown and affected version matrix. No public proof-of-concept code has been verified for this entry.

Detection Methods for CVE-2026-35077

Indicators of Compromise

Unexpected absence of configuration, log, or binary files associated with the affected service
Service restart loops or startup failures following authenticated management sessions
Audit log entries showing ugw-delete-file invocations with paths containing ../ sequences or absolute paths outside the intended working directory
Authentication events from unusual source addresses immediately preceding file deletion calls

Detection Strategies

Enable verbose logging on the management interface to capture all method invocations and their parameters
Deploy file integrity monitoring on configuration directories, service binaries, and credential stores
Correlate authentication events with file system change events to identify abuse patterns
Alert on any invocation of ugw-delete-file against paths outside the application's designated data directory

Monitoring Recommendations

Forward management interface logs and file integrity events to a centralized SIEM for correlation
Baseline normal file deletion behavior for the service account and alert on deviations
Monitor for sudden spikes in authentication failures preceding successful logins, which may indicate credential brute force

How to Mitigate CVE-2026-35077

Immediate Actions Required

Apply the vendor-supplied update referenced in CERT-VDE VDE-2026-039 as soon as it is available for your environment
Restrict network access to the management interface to trusted administrative networks only
Rotate credentials for all user accounts that have access to the affected interface
Audit existing accounts and remove unnecessary low-privileged users that can reach the ugw-delete-file method

Patch Information

Consult the CERT-VDE Security Advisory VDE-2026-039 for the authoritative list of fixed versions and upgrade instructions. Verify firmware or software integrity after applying the update.

Workarounds

Place the management interface behind a VPN or jump host to limit exposure to authenticated attackers
Apply network segmentation to isolate the affected device from general user networks
Enforce strong, unique passwords and multi-factor authentication where the platform supports it
Increase logging verbosity and review file deletion events daily until the patch is applied

bash

# Example: restrict management interface access at the network layer
iptables -A INPUT -p tcp --dport 443 -s 10.0.10.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP