# CVE-2021-3774: Meross MSS550X Missing Encryption of Sensitive Data

> An attacker can intercept plain HTTP requests during initial setup to steal Wi-Fi credentials from the Meross Smart Wi-Fi Wall Switch.

- **Severity:** High 7.4 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 5 Nov 2021
- **Updated:** 23 Apr 2025
- **Also known as:** GHSA-p792-3c6f-m4p5

## What is CVE-2021-3774?

CVE-2021-3774 is a high-severity vulnerability in Meross Smart Wi-Fi 2 Way Wall Switch, published on 5 Nov 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Meross Smart Wi-Fi 2 Way Wall Switch (MSS550X), on its 3.1.3 version and before, creates an open Wi-Fi Access Point without the required security measures in its initial setup. This could allow a remote attacker to obtain the Wi-Fi SSID as well as the password configured by the user from Meross app via Http/JSON plain request.

Weakness: CWE-319 (Cleartext Transmission of Sensitive Information)

## Which versions are affected by CVE-2021-3774?

It affects 1 product.


Products: Meross Mss550x Firmware.

## How do I fix CVE-2021-3774?

No fix has been published for CVE-2021-3774 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-3774 being exploited?

There is no known exploitation of CVE-2021-3774 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-3774 and fix it if it is affected.

What it is: CVE-2021-3774 is a high-severity vulnerability in Meross Smart Wi-Fi 2 Way Wall Switch, published on 5 Nov 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-3774 in the wild and no public exploit code.

Affected product: Meross Smart Wi-Fi 2 Way Wall Switch. 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-2021-3774/ (Markdown: https://insights.sbomify.com/CVE-2021-3774/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-3774
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-3774
- OSV: https://osv.dev/vulnerability/CVE-2021-3774

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-3774/
Summaries are generated and may contain mistakes; the official description above is the record.