# CVE-2026-4254: Tenda AC8 HTTP Endpoint SysToolChangePwd doSystemCmd stack-based overflow

> A remote attacker can trigger a stack-based buffer overflow in the Tenda AC8 router's password change endpoint, potentially leading to arbitrary code execution.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 16 Mar 2026
- **Updated:** 16 Mar 2026
- **Also known as:** GHSA-7ppq-fx8r-g889

## What is CVE-2026-4254?

CVE-2026-4254 is a critical memory corruption vulnerability in Tenda Ac8 Firmware, published on 16 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A weakness has been identified in Tenda AC8 up to 16.03.50.11. This vulnerability affects the function doSystemCmd of the file /goform/SysToolChangePwd of the component HTTP Endpoint. This manipulation of the argument local_2c causes stack-based buffer overflow. The attack can be initiated remotely. The exploit has been made available to the public and could be used for attacks.

Weakness: CWE-121 (Stack-based Buffer Overflow), CWE-787 (Out-of-bounds Write), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2026-4254?

It affects 1 product.


Products: Tenda Ac8 Firmware.

## How do I fix CVE-2026-4254?

No fix has been published for CVE-2026-4254 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-4254 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-4254 exists.

## Other vulnerabilities in Tenda Ac8 Firmware

- [CVE-2025-29100](https://insights.sbomify.com/CVE-2025-29100/): Memory corruption in n/a (critical 9.8)
- [CVE-2025-25663](https://insights.sbomify.com/CVE-2025-25663/): Memory corruption in n/a (critical 9.8)
- [CVE-2025-25664](https://insights.sbomify.com/CVE-2025-25664/): Memory corruption in n/a (critical 9.8)
- [CVE-2025-25667](https://insights.sbomify.com/CVE-2025-25667/): Memory corruption in n/a (critical 9.8)
- [CVE-2025-25668](https://insights.sbomify.com/CVE-2025-25668/): Memory corruption in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-4254 and fix it if it is affected.

What it is: CVE-2026-4254 is a critical memory corruption vulnerability in Tenda Ac8 Firmware, published on 16 Mar 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-2026-4254 exists.

Affected product: Tenda Ac8 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-2026-4254/ (Markdown: https://insights.sbomify.com/CVE-2026-4254/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-4254
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-4254
- OSV: https://osv.dev/vulnerability/CVE-2026-4254

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-4254/
Summaries are generated and may contain mistakes; the official description above is the record.