# CVE-2026-4377: Use of Weak Credentials in D-Link DWR-X1820 router

> Attackers can gain unauthorized access to D-Link DWR-X1820 routers by deriving the weak default password from the device's IMEI number.

- **Severity:** Medium 6.0 (`CVSS:4.0/AV:A/AC:H/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N`)
- **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:** 28 May 2026
- **Updated:** 28 May 2026
- **Also known as:** GHSA-624f-p4gg-qwg2

## What is CVE-2026-4377?

CVE-2026-4377 is a medium-severity vulnerability in D-Link Corporation DWR-X1820, published on 28 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Dlink DWR-X1820 router uses weak default password generated from its IMEI number and does not require users to change it. An attacker who knows how passwords are generated can easily crack the default password if they have the device IMEI number.

This issue was fixed in version 1.00B16CP.

Weakness: CWE-1391 (Use of Weak Credentials)

## Which versions are affected by CVE-2026-4377?


## How do I fix CVE-2026-4377?

No fix has been published for CVE-2026-4377 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-4377 being exploited?

There is no known exploitation of CVE-2026-4377 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-4377 and fix it if it is affected.

What it is: CVE-2026-4377 is a medium-severity vulnerability in D-Link Corporation DWR-X1820, published on 28 May 2026. 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-2026-4377 in the wild and no public exploit code.

Affected product: D-Link Corporation DWR-X1820. 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-2026-4377/ (Markdown: https://insights.sbomify.com/CVE-2026-4377/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-4377
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-4377
- OSV: https://osv.dev/vulnerability/CVE-2026-4377

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-4377/
Summaries are generated and may contain mistakes; the official description above is the record.