# CVE-2021-20826: Information disclosure in IDEC PLC

> Attackers can intercept unprotected credentials to gain full access to IDEC PLC web servers, enabling output manipulation or suspension.

- **Severity:** High 7.6 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 24 Dec 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-v3cv-2j8p-p6xh

## What is CVE-2021-20826?

CVE-2021-20826 is a high-severity vulnerability in IDEC PLC, published on 24 Dec 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Unprotected transport of credentials vulnerability in IDEC PLCs (FC6A Series MICROSmart All-in-One CPU module v2.32 and earlier, FC6A Series MICROSmart Plus CPU module v1.91 and earlier, WindLDR v8.19.1 and earlier, WindEDIT Lite v1.3.1 and earlier, and Data File Manager v2.12.1 and earlier) allows an attacker to obtain the PLC Web server user credentials from the communication between the PLC and the software. As a result, the complete access privileges to the PLC Web server may be obtained, and manipulation of the PLC output and/or suspension of the PLC may be conducted.

Weakness: CWE-522 (Insufficiently Protected Credentials)

## Which versions are affected by CVE-2021-20826?

It affects 5 products.


Products: Idec Data File Manager, Idec Microsmart Fc6a Firmware, Idec Microsmart Plus Fc6a Firmware, Idec Windedit, Idec Windldr.

## How do I fix CVE-2021-20826?

No fix has been published for CVE-2021-20826 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-20826 being exploited?

There is no known exploitation of CVE-2021-20826 in the wild and no public exploit code.

## Other vulnerabilities in IDEC PLC

- [CVE-2021-37400](https://insights.sbomify.com/CVE-2021-37400/): Information disclosure in n/a (critical 9.8)
- [CVE-2021-37401](https://insights.sbomify.com/CVE-2021-37401/): Information disclosure in n/a (critical 9.8)
- [CVE-2021-20827](https://insights.sbomify.com/CVE-2021-20827/): Hardcoded credentials in IDEC PLC (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-20826 and fix it if it is affected.

What it is: CVE-2021-20826 is a high-severity vulnerability in IDEC PLC, published on 24 Dec 2021. 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-2021-20826 in the wild and no public exploit code.

Affected product: IDEC PLC. 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-2021-20826/ (Markdown: https://insights.sbomify.com/CVE-2021-20826/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-20826
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-20826
- OSV: https://osv.dev/vulnerability/CVE-2021-20826

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-20826/
Summaries are generated and may contain mistakes; the official description above is the record.