# CVE-2018-6536: Race condition in n/a

> Local attackers can exploit a race condition in Icinga 2 to kill arbitrary processes or escalate privileges by modifying the PID file before root scripts execute.

- **Severity:** Medium 5.5 (`CVSS:3.0/AV:L/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:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 2 Feb 2018
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2018-6536, GHSA-653v-x44f-wmwh, UBUNTU-CVE-2018-6536

## What is CVE-2018-6536?

CVE-2018-6536 is a medium-severity vulnerability in n/a, published on 2 Feb 2018. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An issue was discovered in Icinga 2.x through 2.8.1. The daemon creates an icinga2.pid file after dropping privileges to a non-root account, which might allow local users to kill arbitrary processes by leveraging access to this non-root account for icinga2.pid modification before a root script executes a "kill `cat /pathname/icinga2.pid`" command, as demonstrated by icinga2.init.d.cmake.

Weakness: CWE-732 (Incorrect Permission Assignment for Critical Resource)

## Which versions are affected by CVE-2018-6536?

It affects 1 product.


Products: Icinga Icinga.

## How do I fix CVE-2018-6536?

Apply the vendor's patch.

## Is CVE-2018-6536 being exploited?

There is no known exploitation of CVE-2018-6536 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2025-48057](https://insights.sbomify.com/CVE-2025-48057/): Icinga 2 certificate renewal might incorrectly renew an invalid certificate (critical 9.3)
- [CVE-2020-29663](https://insights.sbomify.com/CVE-2020-29663/): Security feature bypass in n/a (critical 9.1)
- [CVE-2024-24820](https://insights.sbomify.com/CVE-2024-24820/): Icinga Director configuration is susceptible to Cross-Site Request Forgery (high 8.3)
- [CVE-2018-6535](https://insights.sbomify.com/CVE-2018-6535/): Information disclosure in n/a (high 8.1)
- [CVE-2020-14004](https://insights.sbomify.com/CVE-2020-14004/): Path traversal in n/a (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-6536 and fix it if it is affected.

What it is: CVE-2018-6536 is a medium-severity vulnerability in n/a, published on 2 Feb 2018. 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-2018-6536 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-2018-6536/ (Markdown: https://insights.sbomify.com/CVE-2018-6536/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-6536
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-6536
- OSV: https://osv.dev/vulnerability/CVE-2018-6536

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-6536/
Summaries are generated and may contain mistakes; the official description above is the record.