# CVE-2026-2139: Tenda TX9 fast_setting_wifi_set sub_432580 buffer overflow

> A remote buffer overflow in the Tenda TX9 router's Wi-Fi settings allows 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:** 8 Feb 2026
- **Updated:** 23 Feb 2026
- **Also known as:** GHSA-349v-v693-4xhw

## What is CVE-2026-2139?

CVE-2026-2139 is a high-severity memory corruption vulnerability in Tenda TX9, published on 8 Feb 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A vulnerability was determined in Tenda TX9 up to 22.03.02.10_multi. Affected by this vulnerability is the function sub_432580 of the file /goform/fast_setting_wifi_set. This manipulation of the argument ssid causes buffer overflow. The attack may be initiated remotely. The exploit has been publicly disclosed and may be utilized.

Weakness: CWE-120 (Buffer Copy without Checking Size of Input), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2026-2139?

It affects 1 product.


Products: Tenda Tx9 Firmware.

## How do I fix CVE-2026-2139?

No fix has been published for CVE-2026-2139 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-2139 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-2139 exists.

## Other vulnerabilities in Tenda TX9

- [CVE-2026-2138](https://insights.sbomify.com/CVE-2026-2138/): Tenda TX9 SetStaticRouteCfg sub_42D03C buffer overflow (high 8.7)
- [CVE-2026-2140](https://insights.sbomify.com/CVE-2026-2140/): Tenda TX9 setMacFilterCfg sub_4223E0 buffer overflow (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-2139 and fix it if it is affected.

What it is: CVE-2026-2139 is a high-severity memory corruption vulnerability in Tenda TX9, published on 8 Feb 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-2026-2139 exists.

Affected product: Tenda TX9. 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-2026-2139/ (Markdown: https://insights.sbomify.com/CVE-2026-2139/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-2139
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-2139
- OSV: https://osv.dev/vulnerability/CVE-2026-2139

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-2139/
Summaries are generated and may contain mistakes; the official description above is the record.