# CVE-2026-3971: Tenda i3 wifiSSIDset formwrlSSIDset stack-based overflow

> A stack-based buffer overflow in the Tenda i3 router allows remote attackers to execute arbitrary code or cause a denial of service.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Mar 2026
- **Updated:** 12 Mar 2026
- **Also known as:** GHSA-cwx4-752x-q9c8

## What is CVE-2026-3971?

CVE-2026-3971 is a high-severity memory corruption vulnerability in Tenda i3, published on 12 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A vulnerability has been found in Tenda i3 1.0.0.6(2204). Affected by this vulnerability is the function formwrlSSIDset of the file /goform/wifiSSIDset. The manipulation of the argument index/GO leads to stack-based buffer overflow. Remote exploitation of the attack is possible. The exploit has been disclosed to the public and may be used.

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-2026-3971?

It affects 1 product.


Products: Tenda I3 Firmware.

## How do I fix CVE-2026-3971?

No fix has been published for CVE-2026-3971 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-3971 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-3971 exists.

## Other vulnerabilities in Tenda i3

- [CVE-2026-3970](https://insights.sbomify.com/CVE-2026-3970/): Tenda i3 wifiSSIDget formwrlSSIDget stack-based overflow (high 8.7)
- [CVE-2026-3799](https://insights.sbomify.com/CVE-2026-3799/): Tenda i3 setcfm formSetCfm stack-based overflow (high 8.7)
- [CVE-2026-3801](https://insights.sbomify.com/CVE-2026-3801/): Tenda i3 setAutoPing formSetAutoPing stack-based overflow (high 8.7)
- [CVE-2026-3802](https://insights.sbomify.com/CVE-2026-3802/): Tenda i3 exeCommand formexeCommand stack-based overflow (high 8.7)
- [CVE-2026-3803](https://insights.sbomify.com/CVE-2026-3803/): Tenda i3 WifiMacFilterGet formWifiMacFilterGet stack-based overflow (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-3971 and fix it if it is affected.

What it is: CVE-2026-3971 is a high-severity memory corruption vulnerability in Tenda i3, published on 12 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-3971 exists.

Affected product: Tenda i3. 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-2026-3971/ (Markdown: https://insights.sbomify.com/CVE-2026-3971/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-3971
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-3971
- OSV: https://osv.dev/vulnerability/CVE-2026-3971

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-3971/
Summaries are generated and may contain mistakes; the official description above is the record.