# CVE-2026-45313: Sandboxie-Plus sandbox escape via APC injection in GuiServer

Source: https://junglewise.ai/threats/cve-2026-45313-sandboxie-plus-sandbox-escape-via-apc-injection-in-guiserver  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-15. Updated: 2026-07-15  
License: CC BY 4.0 with a link back

CVE-2026-45313 · Severity: high · CVSS 7.7 · Published 2026-07-15

Sandboxie-Plus is an isolation tool used to run applications in a secure 'sandbox' to prevent them from making permanent changes to the host computer. A security flaw in the software's GUI service allows malicious programs running inside the sandbox to break out and execute code on the main system. This bypasses the primary security purpose of the software, potentially allowing malware to infect the host computer or access sensitive user data.

Technologies: [Sandboxie-Plus Sandboxie](https://junglewise.ai/threats/technologies/sandboxie), [Sandboxie-Plus](https://junglewise.ai/threats/technologies/sandboxie-plus). Vendors: [Sandboxie-Plus](https://junglewise.ai/threats/vendors/sandboxie-plus).

## Quick answers

**Is CVE-2026-45313 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-45313 being exploited in the wild.

**How severe is CVE-2026-45313?** High severity, with a CVSS score of 7.7, published 15 July 2026.

**Which products and versions are affected?** Sandboxie-Plus Sandboxie < 1.17.6; Sandboxie-Plus < 1.17.6.

**Is there a fix for CVE-2026-45313?** A patch was published on 2026-05-17: Version 1.17.6 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-45313 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2026-45313?** Check whether you run Sandboxie-Plus Sandboxie or Sandboxie-Plus at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

An unrestricted APC injection vulnerability exists in the GuiServer service (GuiServer.cpp) due to improper validation in the GuiServer::WndHookRegisterSlave and GuiServer::WndHookNotifySlave functions. A sandboxed process can send a GUI_WND_HOOK_REGISTER request with an arbitrary thread ID and function pointer. Because the service runs with SYSTEM privileges, it successfully opens the target thread with THREAD_SET_CONTEXT and executes QueueUserAPC using the attacker-supplied parameters. This allows a sandboxed process to escape its isolation and execute arbitrary code in any unsandboxed process on the host. The issue is fixed in version 1.17.6 (Plus) and 5.72.6 (Classic) by verifying that the target thread belongs to the calling sandboxed process.

## Affected products

- sandboxie-plus Sandboxie-Plus < 1.17.6
- sandboxie-plus Sandboxie < 5.72.6

## Timeline

- 2026-05-17: patched: Version 1.17.6 released
- 2026-05-22: advisory: GitHub Security Advisory published
- 2026-07-15: disclosed: CVE published to NVD

## References

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

## Related threats

- [Sandboxie-Plus privilege escalation via TOCTOU in UpdUtil](https://junglewise.ai/threats/cve-2026-34596-sandboxie-plus-privilege-escalation-via-toctou-in-updutil)
- [Sandboxie-Plus entropy loss in EditPassword hashing](https://junglewise.ai/threats/cve-2026-34527-sandboxie-plus-entropy-loss-in-editpassword-hashing)
- [Sandboxie-Plus stack overflow in NamedPipeServer OpenHandler](https://junglewise.ai/threats/cve-2026-34464-sandboxie-plus-stack-overflow-in-namedpipeserver-openhandler)
- [Sandboxie-Plus stack buffer overflow in ProcessServer](https://junglewise.ai/threats/cve-2026-34462-sandboxie-plus-stack-buffer-overflow-in-processserver)
- [Sandboxie-Plus stack buffer overflow in SbieIniServer RunSbieCtrl](https://junglewise.ai/threats/cve-2026-34461-sandboxie-plus-stack-buffer-overflow-in-sbieiniserver-runsbiectrl)