Vulnerability · Published May 5, 2026 · Assigned by GitHub_M
CVE-2026-34596Sandboxie-Plus local privilege escalation via TOCTOU race condition in UpdUtil addon installation
Medium 5.4
In plain English
A medium-severity security flaw in Sandboxie from sandboxie-plus. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 1% of all known vulnerabilities).
Official 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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| sandboxie-plus | Sandboxie | < 1.17.3 |
Weakness: CWE-367 · 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