CVE-2026-35082 Overview
CVE-2026-35082 is a path traversal vulnerability [CWE-22] in the ugw-logread method. The flaw stems from insufficient validation of user-supplied input. A remote attacker holding low-privilege user credentials can read arbitrary local files on the affected system. The vulnerability was disclosed through CERT@VDE in advisory VDE-2026-039.
Critical Impact
Authenticated remote attackers can exfiltrate sensitive files including configuration data, credentials, and private keys by abusing the ugw-logread method.
Affected Products
- Products exposing the ugw-logread method (see CERT@VDE Security Advisory VDE-2026-039)
- Specific vendor and version details are published in the referenced advisory
Discovery Timeline
- 2026-06-03 - CVE-2026-35082 published to the National Vulnerability Database
- 2026-06-03 - Last updated in NVD database
Technical Details for CVE-2026-35082
Vulnerability Analysis
The ugw-logread method is designed to return log file contents to authorized users. The method accepts a file path or log identifier from the caller and reads the corresponding file. The implementation fails to sanitize directory traversal sequences such as ../ in the user-supplied input. An attacker authenticated with standard user privileges can supply a crafted path that escapes the intended log directory. The method then opens and returns the contents of arbitrary files accessible to the underlying service account.
Because the service typically runs with elevated permissions to read system logs, the attacker can retrieve files such as /etc/passwd, /etc/shadow (where readable), application configuration files, and stored credentials. The vulnerability is exploitable over the network and requires no user interaction.
Root Cause
The root cause is improper limitation of a pathname to a restricted directory [CWE-22]. The ugw-logread handler concatenates or passes user input into a file read operation without canonicalizing the resulting path or validating it against an allowlist of permitted log files.
Attack Vector
An attacker authenticated as a low-privilege user issues a request to the ugw-logread method with a path parameter containing traversal sequences. The exploitation flow involves authenticating with valid user credentials, invoking ugw-logread with a path such as ../../etc/shadow, and receiving the file contents in the response. No additional privileges or social engineering are required.
No public proof-of-concept exploit is currently available. Technical details are described in prose in the vendor advisory. Refer to the CERT@VDE Security Advisory VDE-2026-039 for vendor-confirmed exploitation details.
Detection Methods for CVE-2026-35082
Indicators of Compromise
- Requests to the ugw-logread method containing directory traversal sequences such as ../, ..\, or URL-encoded variants like %2e%2e%2f
- Access attempts referencing sensitive files outside the log directory, including /etc/passwd, /etc/shadow, or application credential files
- Unusual volume of ugw-logread invocations from a single authenticated session
Detection Strategies
- Inspect application and management interface logs for ugw-logread calls with path parameters that resolve outside the expected log directory
- Deploy intrusion detection signatures targeting path traversal patterns in API parameters
- Correlate authenticated user activity with file access patterns that exceed normal log retrieval behavior
Monitoring Recommendations
- Forward management plane and API access logs to a centralized log analytics platform for retention and search
- Alert on any ugw-logread request whose normalized path falls outside the designated log directory
- Monitor for repeated 200-OK responses to ugw-logread calls from accounts that do not routinely access logs
How to Mitigate CVE-2026-35082
Immediate Actions Required
- Apply the vendor-supplied firmware or software update referenced in CERT@VDE Security Advisory VDE-2026-039 as soon as it is available
- Restrict network access to the affected management interface so only trusted administrative networks can reach it
- Audit existing user accounts and revoke unused or weakly authenticated credentials that could be used to invoke ugw-logread
Patch Information
Patch and fixed-version information is published in the CERT@VDE Security Advisory VDE-2026-039. Consult the advisory for the specific affected versions and remediated releases.
Workarounds
- Block external access to the affected service endpoint using network segmentation or firewall rules until patches are deployed
- Enforce strong, unique credentials and enable multi-factor authentication for all accounts permitted to call the management API
- Monitor logs for traversal sequences and disable non-essential user accounts that have access to the ugw-logread method
# Example firewall rule restricting management interface access to trusted subnet
iptables -A INPUT -p tcp --dport <mgmt-port> -s 10.0.10.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport <mgmt-port> -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
