# CVE-2018-6535: Information disclosure in n/a

> Attackers can disclose passwords due to non-constant-time comparison in Icinga, requiring an upgrade to secure credentials.

- **Severity:** High 8.1 (`CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 27 Feb 2018
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2018-6535, GHSA-5535-phc2-4862, UBUNTU-CVE-2018-6535

## What is CVE-2018-6535?

CVE-2018-6535 is a high-severity vulnerability in n/a, published on 27 Feb 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An issue was discovered in Icinga 2.x through 2.8.1. The lack of a constant-time password comparison function can disclose the password to an attacker.

## Which versions are affected by CVE-2018-6535?

It affects 1 product.


Products: Icinga Icinga.

## How do I fix CVE-2018-6535?

Upgrade to a fixed version.

## Is CVE-2018-6535 being exploited?

There is no known exploitation of CVE-2018-6535 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-2020-14004](https://insights.sbomify.com/CVE-2020-14004/): Path traversal in n/a (high 7.8)
- [CVE-2018-6533](https://insights.sbomify.com/CVE-2018-6533/): Privilege escalation in n/a (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-6535 and fix it if it is affected.

What it is: CVE-2018-6535 is a high-severity vulnerability in n/a, published on 27 Feb 2018. 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-2018-6535 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-2018-6535/ (Markdown: https://insights.sbomify.com/CVE-2018-6535/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-6535
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-6535
- OSV: https://osv.dev/vulnerability/CVE-2018-6535

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-6535/
Summaries are generated and may contain mistakes; the official description above is the record.