# CVE-2025-6400: TOTOLINK N300RH HTTP POST Message formPortFw buffer overflow

> Remote attackers can trigger a buffer overflow in the HTTP POST handler to potentially execute arbitrary code on TOTOLINK N300RH routers.

- **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 Jun 2025
- **Updated:** 23 Jun 2025
- **Also known as:** GHSA-4f49-fqv9-jwhv

## What is CVE-2025-6400?

CVE-2025-6400 is a high-severity memory corruption vulnerability in TOTOLINK N300RH, published on 21 Jun 2025. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A vulnerability was found in TOTOLINK N300RH 6.1c.1390_B20191101 and classified as critical. Affected by this issue is some unknown functionality of the file /boafrm/formPortFw of the component HTTP POST Message Handler. The manipulation of the argument service_type leads to buffer overflow. The attack may be launched remotely. The exploit has been disclosed to the public and may be used.

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-2025-6400?

It affects 1 product.


Products: Totolink N300rh Firmware.

## How do I fix CVE-2025-6400?

No fix has been published for CVE-2025-6400 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-6400 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-6400 exists.

## Other vulnerabilities in TOTOLINK N300RH

- [CVE-2026-3301](https://insights.sbomify.com/CVE-2026-3301/): Totolink N300RH Web Management cstecgi.cgi setWebWlanIdx os command injection (critical 9.3)
- [CVE-2026-3696](https://insights.sbomify.com/CVE-2026-3696/): Totolink N300RH CGI cstecgi.cgi setWiFiWpsConfig os command injection (medium 6.9)
- [CVE-2025-4849](https://insights.sbomify.com/CVE-2025-4849/): TOTOLINK N300RH cstecgi.cgi CloudACMunualUpdateUserdata command injection (medium 5.3)
- [CVE-2025-4850](https://insights.sbomify.com/CVE-2025-4850/): TOTOLINK N300RH cstecgi.cgi setUnloadUserData command injection (medium 5.3)
- [CVE-2025-4851](https://insights.sbomify.com/CVE-2025-4851/): TOTOLINK N300RH cstecgi.cgi setUploadUserData command injection (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-6400 and fix it if it is affected.

What it is: CVE-2025-6400 is a high-severity memory corruption vulnerability in TOTOLINK N300RH, published on 21 Jun 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-2025-6400 exists.

Affected product: TOTOLINK N300RH. 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-2025-6400/ (Markdown: https://insights.sbomify.com/CVE-2025-6400/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-6400
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-6400
- OSV: https://osv.dev/vulnerability/CVE-2025-6400

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From sbomify Insights: https://insights.sbomify.com/CVE-2025-6400/
Summaries are generated and may contain mistakes; the official description above is the record.