# CVE-2012-10021: D-Link DIR-605L Captcha Handling Buffer Overflow

> Remote unauthenticated attackers can execute arbitrary code with root privileges via a stack-based buffer overflow in the CAPTCHA handling function.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 31 Jul 2025
- **Updated:** 14 May 2026
- **Also known as:** GHSA-g2h4-mw8p-v523

## What is CVE-2012-10021?

CVE-2012-10021 is a critical memory corruption vulnerability in Dlink Dir-605l Firmware, published on 31 Jul 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A stack-based buffer overflow vulnerability exists in D-Link DIR-605L Wireless N300 Cloud Router firmware versions 1.12 and 1.13 via the getAuthCode() function. The flaw arises from unsafe usage of sprintf() when processing user-supplied CAPTCHA data via the FILECODE parameter in /goform/formLogin. A remote unauthenticated attacker can exploit this to execute arbitrary code with root privileges on the device.

Weakness: CWE-121 (Stack-based Buffer Overflow)

## Which versions are affected by CVE-2012-10021?

It affects 1 product.


Products: Dlink Dir-605l Firmware.

## How do I fix CVE-2012-10021?

No fix has been published for CVE-2012-10021 yet. Limit exposure of the affected software until one is available.

## Is CVE-2012-10021 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2012-10021 exists.

Public exploit code:

- D-Link DIR-605L Captcha Handling Buffer Overflow (metasploit)

## Other vulnerabilities in Dlink Dir-605l Firmware

- [CVE-2021-40655](https://insights.sbomify.com/CVE-2021-40655/): D-Link DIR-605 Router Information Disclosure (high 7.5, exploited in the wild)
- [CVE-2026-42373](https://insights.sbomify.com/CVE-2026-42373/): D-Link DIR-605L B2 Hardcoded Telnet Backdoor Credentials (critical 9.8)
- [CVE-2023-29961](https://insights.sbomify.com/CVE-2023-29961/): Memory corruption in n/a (critical 9.8)
- [CVE-2023-24348](https://insights.sbomify.com/CVE-2023-24348/): Memory corruption in n/a (critical 9.8)
- [CVE-2023-24349](https://insights.sbomify.com/CVE-2023-24349/): Memory corruption in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2012-10021 and fix it if it is affected.

What it is: CVE-2012-10021 is a critical memory corruption vulnerability in Dlink Dir-605l Firmware, published on 31 Jul 2025. 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-2012-10021 exists.

Affected product: Dlink Dir-605l Firmware. 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-2012-10021/ (Markdown: https://insights.sbomify.com/CVE-2012-10021/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2012-10021
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2012-10021
- OSV: https://osv.dev/vulnerability/CVE-2012-10021

---
From sbomify Insights: https://insights.sbomify.com/CVE-2012-10021/
Summaries are generated and may contain mistakes; the official description above is the record.