Sandboxie-Plus CVE-2026-34459

Attacker must already have code execution inside a Sandboxie sandbox with sufficient permissions to send IPC requests to the SbieSvc service process. Applies to both default and Security Hardened Sandbox configurations, as the vulnerability is in the privileged service rather than sandbox policy. Systems with Intel CET/Shadow Stack hardware enforcement prevent ROP chain execution but remain vulnerable to the information disclosure component. Exploitation requires detailed knowledge of target system memory layout to craft functional ROP chains despite high attack complexity (AC:H). No user interaction required (UI:N) once sandboxed code is running. Attack is limited to systems running vulnerable Sandboxie-Plus versions (≤1.17.2) on Windows platforms where SbieSvc service is active.

Real-world risk is significant but nuanced. CVSS 8.8 reflects maximum impact (SYSTEM escalation breaking out of hardened sandboxes, compromising host confidentiality/integrity/availability), but attack complexity is high and requires local code execution inside a sandbox first. This is NOT a remote attack - adversaries must already have foothold code running in a Sandboxie-isolated environment, typical in malware analysis labs, secure browsing scenarios, or zero-trust desktop deployments. No CISA KEV listing and no public POC indicate no widespread exploitation detected, though targeted attacks against security researchers or enterprises using Sandboxie for application isolation remain plausible. The attack prerequisites (attacker-controlled sandboxed process, ability to send IPC requests to SbieSvc, systems without Intel CET) limit exposure compared to typical local privilege escalation vulnerabilities. Priority should be CRITICAL for organizations actively using Sandboxie-Plus for security boundaries (malware sandboxes, browser isolation, enterprise desktop security), but LOW for environments where Sandboxie is absent or used only for compatibility rather than security isolation. Intel CET partially mitigates by preventing ROP execution but leaves the information disclosure unexploited - defenders should not consider CET-enabled systems fully protected. Patch availability in 1.17.3 makes remediation straightforward; delay risk is organizational (update deployment cycles) rather than technical.

A security researcher opens a suspicious executable inside a Sandboxie Security Hardened Sandbox for dynamic malware analysis. The malware, designed to detect sandboxed environments, sends a crafted IPC request to SbieSvc with cbSize=0 to leak 32KB of service process stack memory, extracting return addresses to defeat ASLR and stack cookies to bypass /GS protections. Using this leaked data, the malware constructs a ROP chain targeting known Windows API gadgets and sends a second IPC request with cbSize exceeding 32KB to overflow the SbieSvc stack buffer, pivoting execution to the ROP payload. The chain calls VirtualProtect to mark shellcode as executable and invokes CreateProcess with SYSTEM token to spawn cmd.exe outside the sandbox with full administrative privileges. The attacker now controls the host system, bypassing all sandbox protections and potentially accessing the researcher's network or exfiltrating collected malware samples.