CVE-2021-35027: zyxel zywall_vpn2s_firmware Path Traversal: 'dir/../../filename'

Vulnerability summary

CVE-2021-35027 is a high (CVSS 7.5) Path Traversal: 'dir/../../filename' vulnerability in zyxel zywall_vpn2s_firmware. EPSS estimates a 2.04% chance of exploitation in the next 30 days, higher than 80.9% of scored vulnerabilities.

Timeline

1. 29-09-2021
   PublishedVulnerability first disclosed.
2. 04-08-2024
   Last modifiedVulnerability information updated.

Description

A directory traversal vulnerability in the web server of the Zyxel VPN2S firmware version 1.12 could allow a remote attacker to gain access to sensitive information.

• CWE-27Path Traversal: 'dir/../../filename'The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize multiple internal "../" sequences that can resolve to a location that is outside of that directory.
• CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')The 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.