CVE-2026-34464

Sandboxie-Plus NamedPipeServer OpenHandler stack overflow via unterminated server field

HIGH
8.8
CVSS Score
Published: May 5, 2026 at 07:31 PM UTC
Updated: July 24, 2026 at 10:20 PM UTC
2 products affected across 1 vendorSandboxieSandboxie

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Severity
HIGH8.8
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.17.3
Affected range stops below 1.17.3, so it looks safe — our inference, not a vendor statement
v < 1.17.3
Affected range stops below 1.17.3, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

x_refsource_CONFIRMExploitMitigationVendor Advisory
Source: cverecord
https://github.com/sandboxie-plus/Sandboxie/security/advisories/GHSA-cf8x-f33g-vwfg

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.8HIGHGitHub_M
Vector?

Quick Info

StatusANALYZED
CWE
CWE-121CWE-170

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