CVE-2026-34464 Sandboxie-Plus NamedPipeServer OpenHandler stack overflow via unterminated server field
A stack overflow in Sandboxie-Plus allows sandboxed callers to execute code as SYSTEM, enabling sandbox escape and privilege escalation.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-34464?
CVE-2026-34464 is a high-severity memory corruption vulnerability in sandboxie-plus Sandboxie, published on 5 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Sandboxie-Plus is an open source sandbox-based isolation software for Windows. In versions 1.17.2 and earlier, NamedPipeServer::OpenHandler copies the server field from NAMED_PIPE_OPEN_REQ into a fixed WCHAR pipename[160] stack buffer using wcscat without verifying null termination. The handler only enforces a minimum packet size, and since the service pipe accepts variable-length messages, a sandboxed caller can fill the server[48] field with non-zero data and append additional controlled wide characters after the structure. wcscat then reads past the fixed field and overflows the stack buffer in the SYSTEM service. This message is restricted to sandboxed callers, making it a sandbox escape vector. This can lead to a crash of the SbieSvc service or potential code execution as SYSTEM. This issue has been fixed in version 1.17.3.
Which versions are affected by CVE-2026-34464?
It affects 1 product.
Products include Sandboxie-Plus Sandboxie.
How do I fix CVE-2026-34464?
No fix has been published for CVE-2026-34464 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-34464 being exploited?
There is no known exploitation of CVE-2026-34464 in the wild and no public exploit code.
Other vulnerabilities in sandboxie-plus Sandboxie
- CVE-2018-18748 Security feature bypass in n/a
- CVE-2025-64721 Sandboxie's Integer Overflow in SbieIniServer::RC4Crypt allows sandbox escape and SYSTEM compromise
- CVE-2026-34458 Sandboxie-Plus privilege escalation via INI CRLF injection bypassing EditAdminOnly
- CVE-2024-49360 Path traversal in Sandboxie
- CVE-2026-34459 Sandboxie-Plus sandbox escape via uninitialized memory leak and stack overflow in GetRawInputDeviceInfoSlave
Sources
Also known as GHSA-cf8x-f33g-vwfg.