# CVE-2026-2874: Tenda A21 fast_setting_wifi_set form_fast_setting_wifi_set stack-based overflow

> Remote attackers can trigger a stack-based buffer overflow in the Tenda A21 router via the ssid argument, potentially leading to code execution or service disruption.

- **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:** 21 Feb 2026
- **Updated:** 23 Feb 2026
- **Also known as:** GHSA-mq2p-gcxf-x8gf

## What is CVE-2026-2874?

CVE-2026-2874 is a high-severity memory corruption vulnerability in Tenda A21, published on 21 Feb 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A flaw has been found in Tenda A21 1.0.0.0. Impacted is the function form_fast_setting_wifi_set of the file /goform/fast_setting_wifi_set. Executing a manipulation of the argument ssid can lead to stack-based buffer overflow. It is possible to launch the attack remotely. The exploit has been published and may be used.

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

## Which versions are affected by CVE-2026-2874?

It affects 1 product.


Products: Tenda A21 Firmware.

## How do I fix CVE-2026-2874?

No fix has been published for CVE-2026-2874 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-2874 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-2874 exists.

## Other vulnerabilities in Tenda A21

- [CVE-2026-2870](https://insights.sbomify.com/CVE-2026-2870/): Tenda A21 formSetQosBand set_qosMib_list stack-based overflow (high 8.7)
- [CVE-2026-2871](https://insights.sbomify.com/CVE-2026-2871/): Tenda A21 SetIpMacBind fromSetIpMacBind stack-based overflow (high 8.7)
- [CVE-2026-2872](https://insights.sbomify.com/CVE-2026-2872/): Tenda A21 MAC Filtering Configuration Endpoint setBlackRule set_device_name stack-based overflow (high 8.7)
- [CVE-2026-2873](https://insights.sbomify.com/CVE-2026-2873/): Tenda A21 openSchedWifi setSchedWifi stack-based overflow (high 8.7)
- [CVE-2026-2886](https://insights.sbomify.com/CVE-2026-2886/): Tenda A21 SetOnlineDevName set_device_name stack-based overflow (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-2874 and fix it if it is affected.

What it is: CVE-2026-2874 is a high-severity memory corruption vulnerability in Tenda A21, published on 21 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-2026-2874 exists.

Affected product: Tenda A21. 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-2026-2874/ (Markdown: https://insights.sbomify.com/CVE-2026-2874/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-2874
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-2874
- OSV: https://osv.dev/vulnerability/CVE-2026-2874

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-2874/
Summaries are generated and may contain mistakes; the official description above is the record.