# CVE-2026-40031: MemProcFS < 5.17 DLL/Shared Library Hijacking

> Attackers can achieve arbitrary code execution by placing malicious libraries in the working directory or manipulating environment variables.

- **Severity:** High 8.5 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 8 Apr 2026
- **Updated:** 14 Jul 2026
- **Also known as:** GHSA-wxrw-fvc7-2xmx

## What is CVE-2026-40031?

CVE-2026-40031 is a high-severity vulnerability in ufrisk MemProcFS, published on 8 Apr 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

MemProcFS before 5.17 contains multiple unsafe library-loading patterns that enable DLL and shared-library hijacking across six attack surfaces, including bare-name LoadLibraryU and dlopen calls without path qualification for vmmpyc, libMSCompression, and plugin DLLs. An attacker who places a malicious DLL or shared library in the working directory or manipulates LD_LIBRARY_PATH can achieve arbitrary code execution when MemProcFS loads.

Weakness: CWE-427 (Uncontrolled Search Path Element)

## Which versions are affected by CVE-2026-40031?

It affects 1 product.


Products: Ufrisk Memprocfs.

## How do I fix CVE-2026-40031?

No fix has been published for CVE-2026-40031 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-40031 being exploited?

There is no known exploitation of CVE-2026-40031 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-40031 and fix it if it is affected.

What it is: CVE-2026-40031 is a high-severity vulnerability in ufrisk MemProcFS, published on 8 Apr 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-40031 in the wild and no public exploit code.

Affected product: ufrisk MemProcFS. 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-2026-40031/ (Markdown: https://insights.sbomify.com/CVE-2026-40031/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-40031
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40031
- OSV: https://osv.dev/vulnerability/CVE-2026-40031

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-40031/
Summaries are generated and may contain mistakes; the official description above is the record.