# CVE-2025-9091: Tenda AC20 shadow hard-coded credentials

> Hard-coded credentials in the shadow file allow local attackers to gain elevated privileges and access sensitive data on Tenda AC20 routers.

- **Severity:** Low 2.0 (`CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 17 Aug 2025
- **Updated:** 18 Aug 2025
- **Also known as:** GHSA-vq2h-cfxr-pp9q

## What is CVE-2025-9091?

CVE-2025-9091 is a low-severity vulnerability in Tenda AC20, published on 17 Aug 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A security flaw has been discovered in Tenda AC20 16.03.08.12. Affected by this vulnerability is an unknown functionality of the file /etc_ro/shadow. The manipulation leads to hard-coded credentials. It is possible to launch the attack on the local host. The complexity of an attack is rather high. The exploitation appears to be difficult. The exploit has been disclosed to the public and may be used.

Weakness: CWE-798 (Use of Hard-coded Credentials), CWE-259 (Use of Hard-coded Password)

## Which versions are affected by CVE-2025-9091?

It affects 1 product.


Products: Tenda Ac20 Firmware.

## How do I fix CVE-2025-9091?

No fix has been published for CVE-2025-9091 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-9091 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-9091 exists.

## Other vulnerabilities in Tenda AC20

- [CVE-2025-15356](https://insights.sbomify.com/CVE-2025-15356/): Tenda AC20 PowerSaveSet sscanf buffer overflow (high 8.7)
- [CVE-2025-14654](https://insights.sbomify.com/CVE-2025-14654/): Tenda AC20 httpd setPptpUserList formSetPPTPUserList stack-based overflow (high 8.7)
- [CVE-2025-14655](https://insights.sbomify.com/CVE-2025-14655/): Tenda AC20 httpd SetSysAutoRebbotCfg formSetRebootTimer stack-based overflow (high 8.7)
- [CVE-2025-14656](https://insights.sbomify.com/CVE-2025-14656/): Tenda AC20 openSchedWifi httpd buffer overflow (high 8.7)
- [CVE-2025-13258](https://insights.sbomify.com/CVE-2025-13258/): Tenda AC20 WifiExtraSet buffer overflow (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-9091 and fix it if it is affected.

What it is: CVE-2025-9091 is a low-severity vulnerability in Tenda AC20, published on 17 Aug 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-9091 exists.

Affected product: Tenda AC20. 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-2025-9091/ (Markdown: https://insights.sbomify.com/CVE-2025-9091/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-9091
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-9091
- OSV: https://osv.dev/vulnerability/CVE-2025-9091

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-9091/
Summaries are generated and may contain mistakes; the official description above is the record.