# CVE-2026-11405: Auth bypass in firmware

> A hidden backdoor in Tenda firmware allows attackers to gain admin access to the web interface using a hardcoded password, bypassing normal authentication.

- **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:** 6 Jul 2026
- **Updated:** 8 Jul 2026
- **Also known as:** GHSA-w55r-jjxw-gxrx

## What is CVE-2026-11405?

CVE-2026-11405 is a critical authentication bypass vulnerability in Tenda firmware, published on 6 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The web server binary /bin/httpd contains a hidden backdoor authentication mechanism in the login() function at 004c88b8.

- The function contains a normal authentication path using MD5/hash-based password verification (prod_encode64/PasswordToMd5/check_rand_key).
- After normal authentication fails, it calls GetValue("sys.rzadmin.password") to read a backdoor password from the device configuration.
- It performs a direct strcmp() comparison (plaintext, not hashed) between the config value and the user-supplied password.

A successful match grants role=2 (admin-level access) and creates a valid session. The rzadmin username is never checked — any username works with the backdoor

## Which versions are affected by CVE-2026-11405?


## How do I fix CVE-2026-11405?

No fix has been published for CVE-2026-11405 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-11405 being exploited?

There is no known exploitation of CVE-2026-11405 in the wild and no public exploit code.

Public exploit code:

- CVE-2026-11405 - Draft (github_poc): https://github.com/HORKimhab/CVE-2026-11405

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-11405 and fix it if it is affected.

What it is: CVE-2026-11405 is a critical authentication bypass vulnerability in Tenda firmware, published on 6 Jul 2026. 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-2026-11405 in the wild and no public exploit code.

Affected product: Tenda 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-2026-11405/ (Markdown: https://insights.sbomify.com/CVE-2026-11405/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-11405
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-11405
- OSV: https://osv.dev/vulnerability/CVE-2026-11405

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-11405/
Summaries are generated and may contain mistakes; the official description above is the record.