Executive brief
The installer for the Anthropic Claude desktop application on Windows is vulnerable to a security flaw that could allow a local attacker to gain elevated system permissions. By placing a malicious file in the same folder as the installer, an attacker can trick the setup process into running unauthorized code with administrative rights. This could lead to a full compromise of the affected computer, including unauthorized data access or persistent malware installation.
Technical details
A DLL search-order hijacking vulnerability (CWE-427) exists in the Anthropic Claude for Windows installer (Claude Setup.exe) before version 1.1.3363. The installer attempts to load specific DLLs, such as profapi.dll, from its current working directory instead of secure system paths after User Account Control (UAC) elevation has occurred. A local attacker can exploit this by placing a malicious DLL with a matching name in the same directory as the installer. When a user runs the installer, the malicious code is executed with elevated privileges, leading to local privilege escalation (LPE). The issue is resolved in version 1.1.3363.
Affected products
- Anthropic Claude Desktop - Windows prior to 1.1.3363
Timeline
- 2026-03-31: disclosed
- 2026-03-31: advisory
- 2026-03-31: patched: Fixed in version 1.1.3363