# CVE-2026-42373: D-Link DIR-605L B2 Hardcoded Telnet Backdoor Credentials

> Attackers on the local network can use hardcoded credentials to gain root access to the D-Link DIR-605L router, which is end-of-life and unpatched.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 4 May 2026
- **Updated:** 5 May 2026
- **Also known as:** GHSA-5jm4-j7g4-8xfh

## What is CVE-2026-42373?

CVE-2026-42373 is a critical vulnerability in Dlink Dir-605l Firmware, published on 4 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

D-Link DIR-605L Hardware Revision B2 (End-of-Life, EOL) contains a hardcoded telnet backdoor. The device starts a telnet daemon at boot via /bin/telnetd.sh with the username "Alphanetworks" and the static password "wrgn76_dlwbr_dir605L" read from /etc/alpha_config/image_sign. The custom telnetd binary accepts a -u user:password flag, and the custom login binary uses strcmp() to validate credentials. Successful authentication grants an unauthenticated attacker on the local network a root shell with full administrative control. The device has reached End-of-Life (EOL) and will not receive patches.

Weakness: CWE-798 (Use of Hard-coded Credentials)

## Which versions are affected by CVE-2026-42373?

It affects 1 product.


Products: Dlink Dir-605l Firmware.

## How do I fix CVE-2026-42373?

No fix has been published for CVE-2026-42373 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-42373 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-42373 exists.

## Other vulnerabilities in Dlink Dir-605l Firmware

- [CVE-2021-40655](https://insights.sbomify.com/CVE-2021-40655/): D-Link DIR-605 Router Information Disclosure (high 7.5, exploited in the wild)
- [CVE-2023-29961](https://insights.sbomify.com/CVE-2023-29961/): Memory corruption in n/a (critical 9.8)
- [CVE-2023-24348](https://insights.sbomify.com/CVE-2023-24348/): Memory corruption in n/a (critical 9.8)
- [CVE-2023-24349](https://insights.sbomify.com/CVE-2023-24349/): Memory corruption in n/a (critical 9.8)
- [CVE-2023-24350](https://insights.sbomify.com/CVE-2023-24350/): Memory corruption in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-42373 and fix it if it is affected.

What it is: CVE-2026-42373 is a critical vulnerability in Dlink Dir-605l Firmware, published on 4 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-42373 exists.

Affected product: Dlink Dir-605l Firmware. 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-2026-42373/ (Markdown: https://insights.sbomify.com/CVE-2026-42373/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-42373
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-42373
- OSV: https://osv.dev/vulnerability/CVE-2026-42373

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-42373/
Summaries are generated and may contain mistakes; the official description above is the record.