CVE-2026-45313 sandboxie-plus CVE debrief

Who should care

Users of Sandboxie-Plus versions prior to 1.17.6, security teams, and operators of affected systems should be aware of this vulnerability and take immediate action to apply the patch or implement compensating controls. The vulnerability can be used to escape the sandbox and execute arbitrary code on the host system, potentially leading to a complete compromise of the system.

Technical summary

The vulnerability exists in the GuiServer::WndHookRegisterSlave function in Sandboxie/core/svc/GuiServer.cpp, which stores attacker-supplied hthread and hproc fields from a GUI_WND_HOOK_REGISTER request without validating that the thread belongs to the sandboxed process or that the function pointer is in the caller address space. The GuiServer::WndHookNotifySlave function then calls OpenThread(THREAD_SET_CONTEXT, FALSE, whk->hthread) and QueueUserAPC((PAPCFUNC)whk->hproc, hThread, (ULONG_PTR)req->threadid) as SYSTEM, allowing a sandboxed process to execute arbitrary code in an unsandboxed host process.

Defensive priority

High

Recommended defensive actions

• Apply the patch to upgrade to Sandboxie-Plus version 1.17.6 or later
• Restrict access to the sandboxed environment
• Monitor for suspicious activity
• Implement additional security controls to prevent exploitation
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record was published on 2026-07-15T22:16:48.873Z and last modified on 2026-07-16T14:16:52.180Z. The NVD entry is currently Deferred. There is limited information available about the vulnerability, and defenders should verify the affected scope and severity with the vendor. The CVE record was created based on limited source information, and its accuracy is not guaranteed.

Official resources