# CVE-2026-35556: Plaintext storage of a password in OpenPLC_V3

> Attackers can retrieve plaintext credentials from OpenPLC_V3 to access sensitive information and potentially take over accounts.

- **Severity:** Critical 9.2 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 9 Apr 2026
- **Updated:** 10 Apr 2026
- **Also known as:** GHSA-xgm5-hf6v-855x

## What is CVE-2026-35556?

CVE-2026-35556 is a critical vulnerability in OpenPLC_V3, published on 9 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

OpenPLC_V3 is vulnerable to a Plaintext Storage of a Password vulnerability that could allow an attacker to retrieve credentials and access sensitive information.

Weakness: CWE-256 (Plaintext Storage of a Password)

## Which versions are affected by CVE-2026-35556?

It affects 1 product.


Products: Openplcproject Openplc V3 Firmware.

## How do I fix CVE-2026-35556?

No fix has been published for CVE-2026-35556 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-35556 being exploited?

There is no known exploitation of CVE-2026-35556 in the wild and no public exploit code.

## Other vulnerabilities in OpenPLC_V3

- [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-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)
- [CVE-2024-36980](https://insights.sbomify.com/CVE-2024-36980/): Denial of service in OpenPLC v3 (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-35556 and fix it if it is affected.

What it is: CVE-2026-35556 is a critical vulnerability in OpenPLC_V3, published on 9 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-35556 in the wild and no public exploit code.

Affected product: OpenPLC_V3. 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-2026-35556/ (Markdown: https://insights.sbomify.com/CVE-2026-35556/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-35556
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-35556
- OSV: https://osv.dev/vulnerability/CVE-2026-35556

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-35556/
Summaries are generated and may contain mistakes; the official description above is the record.