# CVE-2021-21963: Information disclosure in Sealevel

> A man-in-the-middle attack on the SeaConnect 370W web server allows attackers to disclose sensitive information.

- **Severity:** High 7.4 (`CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 4 Feb 2022
- **Updated:** 15 Apr 2025
- **Also known as:** GHSA-xf7v-mwgp-rjj7

## What is CVE-2021-21963?

CVE-2021-21963 is a high-severity vulnerability in Sealevel, published on 4 Feb 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An information disclosure vulnerability exists in the Web Server functionality of Sealevel Systems, Inc. SeaConnect 370W v1.3.34. A specially-crafted man-in-the-middle attack can lead to a disclosure of sensitive information. An attacker can perform a man-in-the-middle attack to trigger this vulnerability.

Weakness: CWE-311 (Missing Encryption of Sensitive Data)

## Which versions are affected by CVE-2021-21963?

It affects 1 product.


Products: Sealevel Seaconnect 370w Firmware.

## How do I fix CVE-2021-21963?

No fix has been published for CVE-2021-21963 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-21963 being exploited?

There is no known exploitation of CVE-2021-21963 in the wild and no public exploit code.

## Other vulnerabilities in Sealevel

- [CVE-2021-21960](https://insights.sbomify.com/CVE-2021-21960/): Memory corruption in Sealevel (critical 10.0)
- [CVE-2021-21961](https://insights.sbomify.com/CVE-2021-21961/): Memory corruption in Sealevel (critical 10.0)
- [CVE-2021-21962](https://insights.sbomify.com/CVE-2021-21962/): Memory corruption in Sealevel (critical 9.0)
- [CVE-2021-21964](https://insights.sbomify.com/CVE-2021-21964/): Denial of service in Sealevel (high 8.6)
- [CVE-2021-21965](https://insights.sbomify.com/CVE-2021-21965/): Denial of service in Sealevel (high 8.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-21963 and fix it if it is affected.

What it is: CVE-2021-21963 is a high-severity vulnerability in Sealevel, published on 4 Feb 2022. 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-2021-21963 in the wild and no public exploit code.

Affected product: Sealevel. 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-2021-21963/ (Markdown: https://insights.sbomify.com/CVE-2021-21963/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-21963
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-21963
- OSV: https://osv.dev/vulnerability/CVE-2021-21963

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-21963/
Summaries are generated and may contain mistakes; the official description above is the record.