CVE-2021-26736: zscaler client_connector Improper Input Validation

Vulnerability summary

CVE-2021-26736 is a high (CVSS 7.8) Improper Input Validation vulnerability in zscaler client_connector. EPSS estimates a 0.22% chance of exploitation in the next 30 days, higher than 12.4% of scored vulnerabilities.

Timeline

1. 23-10-2023
   PublishedVulnerability first disclosed.
2. 27-02-2025
   Last modifiedVulnerability information updated.

Description

Multiple vulnerabilities in the Zscaler Client Connector Installer and Uninstaller for Windows prior to 3.6 allowed execution of binaries from a low privileged path. A local adversary may be able to execute code with SYSTEM privileges.

• CWE-20Improper Input ValidationThe product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
• 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.