# CVE-2025-7421: Tenda O3V2 httpd operateMacFilter fromMacFilterModify stack-based overflow

> Remote attackers can trigger a stack-based buffer overflow in the Tenda O3V2 router's httpd service via the mac argument, potentially leading to code execution.

- **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:** 11 Jul 2025
- **Updated:** 11 Jul 2025
- **Also known as:** GHSA-m965-pw66-9w65

## What is CVE-2025-7421?

CVE-2025-7421 is a high-severity memory corruption vulnerability in Tenda O3V2, published on 11 Jul 2025. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A vulnerability was found in Tenda O3V2 1.0.0.12(3880). It has been rated as critical. This issue affects the function fromMacFilterModify of the file /goform/operateMacFilter of the component httpd. The manipulation of the argument mac leads to stack-based buffer overflow. The attack may be initiated remotely. The exploit has been disclosed to the public 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-2025-7421?

It affects 1 product.


Products: Tenda O3 Firmware.

## How do I fix CVE-2025-7421?

No fix has been published for CVE-2025-7421 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-7421 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-7421 exists.

## Other vulnerabilities in Tenda O3V2

- [CVE-2025-55613](https://insights.sbomify.com/CVE-2025-55613/): Memory corruption in n/a (critical 9.8)
- [CVE-2024-36604](https://insights.sbomify.com/CVE-2024-36604/): Command injection in n/a (critical 9.8)
- [CVE-2025-7422](https://insights.sbomify.com/CVE-2025-7422/): Tenda O3V2 httpd setNetworkService setAutoReboot stack-based overflow (high 8.7)
- [CVE-2025-7423](https://insights.sbomify.com/CVE-2025-7423/): Tenda O3V2 httpd setWrlFilterList formWifiMacFilterSet stack-based overflow (high 8.7)
- [CVE-2025-7416](https://insights.sbomify.com/CVE-2025-7416/): Tenda O3V2 httpd setSysTimeInfo fromSysToolTime stack-based overflow (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-7421 and fix it if it is affected.

What it is: CVE-2025-7421 is a high-severity memory corruption vulnerability in Tenda O3V2, published on 11 Jul 2025. 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-2025-7421 exists.

Affected product: Tenda O3V2. 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-2025-7421/ (Markdown: https://insights.sbomify.com/CVE-2025-7421/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-7421
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-7421
- OSV: https://osv.dev/vulnerability/CVE-2025-7421

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-7421/
Summaries are generated and may contain mistakes; the official description above is the record.