# CVE-2026-34596: Sandboxie-Plus privilege escalation via TOCTOU in UpdUtil

Source: https://junglewise.ai/threats/cve-2026-34596-sandboxie-plus-privilege-escalation-via-toctou-in-updutil  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-05. Updated: 2026-07-25  
License: CC BY 4.0 with a link back

CVE-2026-34596 · Severity: high · CVSS 7 · Published 2026-05-05

Sandboxie-Plus is a security tool used to run applications in an isolated environment to protect the rest of the computer. A flaw in how it installs optional add-ons allows a standard user to trick the system into running malicious code with the highest possible administrative privileges (SYSTEM). This could allow an attacker to take full control of the computer without triggering any security warnings or administrator prompts.

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-2026-34596 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-34596 being exploited in the wild.

**How severe is CVE-2026-34596?** High severity, with a CVSS score of 7, published 5 May 2026.

**Which products and versions are affected?** Sandboxie-Plus <= 1.17.2.

**Is there a fix for CVE-2026-34596?** A patch was published on 2026-05-05: Fixed in version 1.17.3 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-34596 attacked?** It is attacked with local access, in a network appliance.

**Am I affected by CVE-2026-34596?** 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

A Time-of-Check-to-Time-of-Use (TOCTOU) race condition exists in the UpdUtil.exe component of Sandboxie-Plus during addon installation. When a user initiates an addon install via the SandMan interface, the SbieSvc service spawns UpdUtil.exe with SYSTEM privileges. However, the utility stages installation files in the user-writable %TEMP%\sandboxie-updater directory. While UpdUtil verifies the SHA-256 hashes of the downloaded files against a signed manifest, there is a timing window between this verification and the subsequent extraction/execution by install.bat. An unprivileged local attacker can replace the verified 'files.cab' with a malicious version, leading to arbitrary code execution as NT AUTHORITY\SYSTEM without a UAC prompt. This issue is resolved in version 1.17.3.

## Affected products

- sandboxie-plus Sandboxie-Plus <= 1.17.2

## Timeline

- 2026-05-04: advisory: Vendor advisory published on GitHub
- 2026-05-05: disclosed: CVE published to NVD
- 2026-05-05: patched: Fixed in version 1.17.3

## References

- [https://github.com/sandboxie-plus/Sandboxie/security/advisories/GHSA-xjvp-63f2-v585](https://github.com/sandboxie-plus/Sandboxie/security/advisories/GHSA-xjvp-63f2-v585)

## Related threats

- [Sandboxie-Plus sandbox escape via APC injection in GuiServer](https://junglewise.ai/threats/cve-2026-45313-sandboxie-plus-sandbox-escape-via-apc-injection-in-guiserver)
- [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)