# CVE-2026-34459: Sandboxie-Plus sandbox escape via uninitialized memory leak and stack overflow in GetRawInputDeviceInfoSlave

> A sandboxed process can escape isolation and gain SYSTEM privileges by chaining an information leak with a stack buffer overflow in the service handler.

- **Severity:** High 8.8 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 5 May 2026
- **Updated:** 7 May 2026
- **Also known as:** GHSA-7cpc-5hv7-rfmh

## What is CVE-2026-34459?

CVE-2026-34459 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, 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.

Weakness: CWE-121 (Stack-based Buffer Overflow)

## Which versions are affected by CVE-2026-34459?

It affects 1 product.


Products: Sandboxie-Plus Sandboxie.

## How do I fix CVE-2026-34459?

No fix has been published for CVE-2026-34459 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-34459 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34459 exists.

## Other vulnerabilities in sandboxie-plus Sandboxie

- [CVE-2018-18748](https://insights.sbomify.com/CVE-2018-18748/): Security feature bypass in n/a (critical 10.0)
- [CVE-2025-64721](https://insights.sbomify.com/CVE-2025-64721/): Sandboxie's Integer Overflow in SbieIniServer::RC4Crypt allows sandbox escape and SYSTEM compromise (critical 9.9)
- [CVE-2026-34458](https://insights.sbomify.com/CVE-2026-34458/): Sandboxie-Plus privilege escalation via INI CRLF injection bypassing EditAdminOnly (critical 9.3)
- [CVE-2024-49360](https://insights.sbomify.com/CVE-2024-49360/): Path traversal in Sandboxie (critical 9.2)
- [CVE-2026-34464](https://insights.sbomify.com/CVE-2026-34464/): Sandboxie-Plus NamedPipeServer OpenHandler stack overflow via unterminated server field (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-34459 and fix it if it is affected.

What it is: CVE-2026-34459 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.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34459 exists.

Affected product: sandboxie-plus Sandboxie. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-34459/ (Markdown: https://insights.sbomify.com/CVE-2026-34459/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34459
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34459
- OSV: https://osv.dev/vulnerability/CVE-2026-34459

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-34459/
Summaries are generated and may contain mistakes; the official description above is the record.