# CVE-2025-4849: TOTOLINK N300RH cstecgi.cgi CloudACMunualUpdateUserdata command injection

> Remote attackers can execute arbitrary commands on TOTOLINK N300RH routers via the CloudACMunualUpdateUserdata function in cstecgi.cgi.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N`)
- **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:** 18 May 2025
- **Updated:** 19 May 2025
- **Also known as:** GHSA-7f4f-7v48-7gv6

## What is CVE-2025-4849?

CVE-2025-4849 is a medium-severity command injection vulnerability in TOTOLINK N300RH, published on 18 May 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. It has been rated as critical. Affected by this issue is the function CloudACMunualUpdateUserdata of the file /cgi-bin/cstecgi.cgi. The manipulation of the argument url leads to command injection. The attack may be launched remotely. The exploit has been disclosed to the public and may be used.

Weakness: CWE-77 (Improper Neutralization of Special Elements used in a Command), CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component)

## Which versions are affected by CVE-2025-4849?

It affects 1 product.


Products: Totolink N300rh Firmware.

## How do I fix CVE-2025-4849?

No fix has been published for CVE-2025-4849 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-4849 being exploited?

There is no known exploitation of CVE-2025-4849 in the wild and no public exploit code.

## 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-2025-6400](https://insights.sbomify.com/CVE-2025-6400/): TOTOLINK N300RH HTTP POST Message formPortFw buffer overflow (high 8.7)
- [CVE-2026-3696](https://insights.sbomify.com/CVE-2026-3696/): Totolink N300RH CGI cstecgi.cgi setWiFiWpsConfig os command injection (medium 6.9)
- [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-2025-4849 and fix it if it is affected.

What it is: CVE-2025-4849 is a medium-severity command injection vulnerability in TOTOLINK N300RH, published on 18 May 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-4849 in the wild and no public exploit code.

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-2025-4849/ (Markdown: https://insights.sbomify.com/CVE-2025-4849/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-4849
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-4849
- OSV: https://osv.dev/vulnerability/CVE-2025-4849

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From sbomify Insights: https://insights.sbomify.com/CVE-2025-4849/
Summaries are generated and may contain mistakes; the official description above is the record.