CVE-2026-34459: Sandboxie-Plus is an open source sandbox-based isolation software for Windows. In versions 1.17.2 and earlier, the SbieSvc proxy service's GetRawInput...

Description

Sandboxie-Plus is an open source sandbox-based isolation software for Windows. In versions 1.17.2 and earlier, the SbieSvc proxy service's GetRawInputDeviceInfoSlave handler contains two vulnerabilities that can be chained for sandbox escape. First, when a sandboxed process sends an IPC request with cbSize set to 0, up to 32KB of uninitialized stack memory from the service process is returned, leaking return addresses and stack cookies which bypass ASLR and /GS protections. Second, the handler performs a memcpy with an attacker-controlled length without verifying it fits within the 32KB stack buffer, enabling a stack buffer overflow. By chaining the information leak with the overflow, a sandboxed process can execute a ROP chain to achieve SYSTEM privilege escalation, even from a Security Hardened Sandbox. Hardware-enforced shadow stacks (Intel CET) prevent the ROP chain execution but do not mitigate the information leak. This issue has been fixed in version 1.17.3.

Metrics

CVSS 3.1

8.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CVSS 4.0

8.8/10

CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

0.14%

3.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-121

Affected Software

Vendor	Product	Versions
Sandboxie-Plus	Sandboxie	< 1.17.3

References

https://github.com/sandboxie-plus/Sandboxie/security/advisories/GHSA-7cpc-5hv7-rfmhExploit, Mitigation, Vendor Advisory
https://github.com/sandboxie-plus/Sandboxie/security/advisories/GHSA-7cpc-5hv7-rfmhExploit, Mitigation, Vendor Advisory

Timeline

Published: May 5, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-34459?

Sandboxie-Plus is an open source sandbox-based isolation software for Windows. In versions 1.17.2 and earlier, the SbieSvc proxy service's GetRawInputDeviceInfoSlave handler contains two vulnerabilities that can be chained for sandbox escape. First, when a sandboxed process sends an IPC request with cbSize set to 0, up to 32KB of uninitialized stack memory from the service process is returned, leaking return addresses and stack cookies which bypass ASLR and /GS protections. Second, the handler performs a memcpy with an attacker-controlled length without verifying it fits within the 32KB stack buffer, enabling a stack buffer overflow. By chaining the information leak with the overflow, a sandboxed process can execute a ROP chain to achieve SYSTEM privilege escalation, even from a Security Hardened Sandbox. Hardware-enforced shadow stacks (Intel CET) prevent the ROP chain execution but do not mitigate the information leak. This issue has been fixed in version 1.17.3.

How severe is CVE-2026-34459?

CVE-2026-34459 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 0.14% probability of exploitation in the next 30 days.

How do I fix CVE-2026-34459?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.