# CVE-2021-31624: Memory corruption in n/a

> Attackers can execute arbitrary code on Tenda AC9 routers via a buffer overflow in the urls parameter.

- **Severity:** High 8.8 (`CVSS:3.1/AV:A/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:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 29 Oct 2021
- **Updated:** 9 Jul 2026
- **Also known as:** GHSA-qvhc-5474-w39h

## What is CVE-2021-31624?

CVE-2021-31624 is a high-severity memory corruption vulnerability in n/a, published on 29 Oct 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Buffer Overflow vulnerability in Tenda AC9 V1.0 through V15.03.05.19(6318), and AC9 V3.0 V15.03.06.42_multi, allows attackers to execute arbitrary code via the urls parameter.

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

## Which versions are affected by CVE-2021-31624?

It affects 1 product.


Products: Tendacn Ac9 Firmware.

## How do I fix CVE-2021-31624?

No fix has been published for CVE-2021-31624 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-31624 being exploited?

There is no known exploitation of CVE-2021-31624 in the wild and no public exploit code.

Public exploit code:

- Hands-on cybersecurity and CTF labs covering tabnabbing, login security, web reconnaissance, admin access, service discovery, Nmap, Netdiscover, CVE-2020-23546, CVE-2021-31624, and Red Reclaim. (github_poc): https://github.com/sifatnotes/Learn-SecByte-CTF-Labs-Tabnabbing-Web-Recon-Nmap-Netdiscover-CVE-Labs

## Other vulnerabilities in n/a

- [CVE-2023-40942](https://insights.sbomify.com/CVE-2023-40942/): Memory corruption in n/a (critical 9.8)
- [CVE-2018-7561](https://insights.sbomify.com/CVE-2018-7561/): Memory corruption in n/a (critical 9.8)
- [CVE-2021-31627](https://insights.sbomify.com/CVE-2021-31627/): Memory corruption in n/a (high 8.8)
- [CVE-2020-20746](https://insights.sbomify.com/CVE-2020-20746/): Memory corruption in n/a (high 7.2)
- [CVE-2025-29032](https://insights.sbomify.com/CVE-2025-29032/): Memory corruption in n/a (medium 5.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-31624 and fix it if it is affected.

What it is: CVE-2021-31624 is a high-severity memory corruption vulnerability in n/a, published on 29 Oct 2021. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-31624 in the wild and no public exploit code.

Affected product: n/a. 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-2021-31624/ (Markdown: https://insights.sbomify.com/CVE-2021-31624/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-31624
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-31624
- OSV: https://osv.dev/vulnerability/CVE-2021-31624

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-31624/
Summaries are generated and may contain mistakes; the official description above is the record.