# CVE-2026-31156: Path traversal in n/a

> An attacker can read arbitrary files by exploiting a path injection vulnerability in OpenPLC's command-line file operations.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 13 May 2026
- **Updated:** 5 Jul 2026
- **Also known as:** GHSA-p6vg-5mm7-744x

## What is CVE-2026-31156?

CVE-2026-31156 is a medium-severity path traversal vulnerability in n/a, published on 13 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A path injection vulnerability exists in OpenPLC v3 (2c82b0e79c53f8c1f1458eee15fec173400d6e1a) as the binary program compiled from glue_generator.cpp does not perform any validation on the file path parameters passed via the command line. The user-controlled input parameters are directly passed to the underlying file operation functions (fopen/ifstream/ofstream) for file reading and writing. An attacker can exploit this vulnerability by constructing a malicious path to read arbitrary readable files.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-31156?

It affects 1 product.


Products: Openplcproject Openplc V3 Firmware.

## How do I fix CVE-2026-31156?

No fix has been published for CVE-2026-31156 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-31156 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-31156 exists.

Public exploit code:

- There is a path injection vulnerability in OpenPLC-v3, which arises from the program not performing any validity checks on the file path parameters passed in from the command line. Attackers can read any readable file by constructing malicious paths, posing a risk of information leakage. (github_poc): https://github.com/unicorn-hyh/CVE-2026-31156

## Other vulnerabilities in n/a

- [CVE-2026-28205](https://insights.sbomify.com/CVE-2026-28205/): Initialization of a resource with an insecure default in OpenPLC_V3 (critical 9.2)
- [CVE-2026-35556](https://insights.sbomify.com/CVE-2026-35556/): Plaintext storage of a password in OpenPLC_V3 (critical 9.2)
- [CVE-2024-34026](https://insights.sbomify.com/CVE-2024-34026/): Memory corruption in OpenPLC v3 (critical 9.0)
- [CVE-2021-31630](https://insights.sbomify.com/CVE-2021-31630/): Command injection in n/a (high 8.8)
- [CVE-2026-35063](https://insights.sbomify.com/CVE-2026-35063/): Missing Authorization in OpenPLC_V3 (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-31156 and fix it if it is affected.

What it is: CVE-2026-31156 is a medium-severity path traversal vulnerability in n/a, published on 13 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-31156 exists.

Affected product: n/a. 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-2026-31156/ (Markdown: https://insights.sbomify.com/CVE-2026-31156/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31156
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31156
- OSV: https://osv.dev/vulnerability/CVE-2026-31156

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31156/
Summaries are generated and may contain mistakes; the official description above is the record.