# CVE-2023-7221: Totolink T6 HTTP POST Request main buffer overflow

> Remote attackers can trigger a buffer overflow in the login handler of Totolink T6 routers, potentially leading to code execution or service disruption.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 9 Jan 2024
- **Updated:** 14 May 2025
- **Also known as:** GHSA-c653-w7m8-34r2

## What is CVE-2023-7221?

CVE-2023-7221 is a critical memory corruption vulnerability in Totolink T6, published on 9 Jan 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability was found in Totolink T6 4.1.9cu.5241_B20210923. It has been classified as critical. This affects the function main of the file /cgi-bin/cstecgi.cgi?action=login of the component HTTP POST Request Handler. The manipulation of the argument v41 leads to buffer overflow. It is possible to initiate the attack remotely. The exploit has been disclosed to the public and may be used. The associated identifier of this vulnerability is VDB-249855. NOTE: The vendor was contacted early about this disclosure but did not respond in any way.

Weakness: CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2023-7221?

It affects 1 product.


Products: Totolink T6 Firmware.

## How do I fix CVE-2023-7221?

No fix has been published for CVE-2023-7221 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-7221 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-7221 exists.

## Other vulnerabilities in Totolink T6

- [CVE-2022-38823](https://insights.sbomify.com/CVE-2022-38823/): Hardcoded credentials in n/a (critical 9.8)
- [CVE-2022-38826](https://insights.sbomify.com/CVE-2022-38826/): Command injection in n/a (critical 9.8)
- [CVE-2022-38827](https://insights.sbomify.com/CVE-2022-38827/): Memory corruption in n/a (critical 9.8)
- [CVE-2022-38828](https://insights.sbomify.com/CVE-2022-38828/): Command injection in n/a (critical 9.8)
- [CVE-2022-25084](https://insights.sbomify.com/CVE-2022-25084/): Command injection in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-7221 and fix it if it is affected.

What it is: CVE-2023-7221 is a critical memory corruption vulnerability in Totolink T6, published on 9 Jan 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-7221 exists.

Affected product: Totolink T6. 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-2023-7221/ (Markdown: https://insights.sbomify.com/CVE-2023-7221/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-7221
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-7221
- OSV: https://osv.dev/vulnerability/CVE-2023-7221

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-7221/
Summaries are generated and may contain mistakes; the official description above is the record.