# CVE-2021-45757: Memory corruption in n/a

> A buffer overflow in the blocking.cgi script of ASUS AC68U routers allows attackers to cause a denial of service.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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:** 23 Mar 2022
- **Updated:** 9 Jul 2026
- **Also known as:** GHSA-fhfv-jcfj-9cg7

## What is CVE-2021-45757?

CVE-2021-45757 is a high-severity memory corruption vulnerability in n/a, published on 23 Mar 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

ASUS AC68U <=3.0.0.4.385.20852 is affected by a buffer overflow in blocking.cgi, which may cause a denial of service (DoS).

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

## Which versions are affected by CVE-2021-45757?

It affects 1 product.


Products: Asus Rt-Ac68u Firmware.

## How do I fix CVE-2021-45757?

No fix has been published for CVE-2021-45757 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-45757 being exploited?

There is no known exploitation of CVE-2021-45757 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2021-37315](https://insights.sbomify.com/CVE-2021-37315/): Path traversal in n/a (critical 9.1)
- [CVE-2021-37317](https://insights.sbomify.com/CVE-2021-37317/): Path traversal in n/a (critical 9.1)
- [CVE-2021-37316](https://insights.sbomify.com/CVE-2021-37316/): SQL injection in n/a (high 7.5)
- [CVE-2018-0582](https://insights.sbomify.com/CVE-2018-0582/): Cross-site scripting in RT-AC68U (medium 6.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-45757 and fix it if it is affected.

What it is: CVE-2021-45757 is a high-severity memory corruption vulnerability in n/a, published on 23 Mar 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-45757 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-2021-45757/ (Markdown: https://insights.sbomify.com/CVE-2021-45757/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-45757
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-45757
- OSV: https://osv.dev/vulnerability/CVE-2021-45757

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-45757/
Summaries are generated and may contain mistakes; the official description above is the record.