# CVE-2021-36613: Null dereference in n/a

> An authenticated remote attacker can cause a Denial of Service in Mikrotik RouterOS via a NULL pointer dereference in the ptp process.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **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:** 11 May 2022
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-2hw5-388c-g7xj

## What is CVE-2021-36613?

CVE-2021-36613 is a medium-severity vulnerability in Mikrotik Routeros, published on 11 May 2022. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Mikrotik RouterOs before stable 6.48.2 suffers from a memory corruption vulnerability in the ptp process. An authenticated remote attacker can cause a Denial of Service (NULL pointer dereference).

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2021-36613?

It affects 1 product.


Products: Mikrotik Routeros.

## How do I fix CVE-2021-36613?

No fix has been published for CVE-2021-36613 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-36613 being exploited?

There is no known exploitation of CVE-2021-36613 in the wild and no public exploit code.

## Other vulnerabilities in Mikrotik Routeros

- [CVE-2018-7445](https://insights.sbomify.com/CVE-2018-7445/): MikroTik RouterOS Stack-Based Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2026-86060](https://insights.sbomify.com/CVE-2026-86060/): MikroTik RouterOS Improper Neutralization of Argument Delimiters in a Command (critical 9.2, exploited in the wild)
- [CVE-2018-14847](https://insights.sbomify.com/CVE-2018-14847/): MikroTik Router OS Directory Traversal (critical 9.1, exploited in the wild)
- [CVE-2026-67277](https://insights.sbomify.com/CVE-2026-67277/): MikroTik RouterOS Missing Authentication for Critical Function (high 8.8, exploited in the wild)
- [CVE-2026-67279](https://insights.sbomify.com/CVE-2026-67279/): Mikrotik RouterOS Improper Enforcement of Behavioral Workflow (medium 6.9, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-36613 and fix it if it is affected.

What it is: CVE-2021-36613 is a medium-severity vulnerability in Mikrotik Routeros, published on 11 May 2022. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-36613 in the wild and no public exploit code.

Affected product: Mikrotik Routeros. 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-2021-36613/ (Markdown: https://insights.sbomify.com/CVE-2021-36613/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-36613
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-36613
- OSV: https://osv.dev/vulnerability/CVE-2021-36613

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-36613/
Summaries are generated and may contain mistakes; the official description above is the record.