# CVE-2026-34461: Sandboxie-Plus SbieIniServer RunSbieCtrl stack buffer overflow allows local privilege escalation

> A stack buffer overflow in Sandboxie-Plus allows local attackers to execute code as SYSTEM via the SbieIniServer service.

- **Severity:** High 7.3 (`CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **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-wpjw-jh2p-gwx7

## What is CVE-2026-34461?

CVE-2026-34461 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 SbieIniServer RunSbieCtrl handler contains a stack buffer overflow. The MSGID_SBIE_INI_RUN_SBIE_CTRL message is handled before normal sandbox and impersonation checks, and for non-sandboxed callers, the handler copies the trailing message payload into a fixed-size WCHAR ctrlCmd[128] stack buffer using memcpy without verifying the length fits within the buffer. The service pipe is created with a NULL DACL, allowing any local interactive process to connect and send an oversized payload to overflow the stack. 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.

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

## Which versions are affected by CVE-2026-34461?

It affects 1 product.


Products: Sandboxie-Plus Sandboxie.

## How do I fix CVE-2026-34461?

No fix has been published for CVE-2026-34461 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-34461 being exploited?

There is no known exploitation of CVE-2026-34461 in the wild and no public exploit code.

## 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-2026-34459](https://insights.sbomify.com/CVE-2026-34459/): Sandboxie-Plus sandbox escape via uninitialized memory leak and stack overflow in GetRawInputDeviceInfoSlave (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-34461 and fix it if it is affected.

What it is: CVE-2026-34461 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: There is no known exploitation of CVE-2026-34461 in the wild and no public exploit code.

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-2026-34461/ (Markdown: https://insights.sbomify.com/CVE-2026-34461/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34461
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34461
- OSV: https://osv.dev/vulnerability/CVE-2026-34461

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-34461/
Summaries are generated and may contain mistakes; the official description above is the record.