# CVE-2026-48548: Nagios Core CSRF via cmd.cgi


- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 26 Aug 2026
- **Updated:** 26 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-48548, GHSA-5xj4-4632-2x3r, UBUNTU-CVE-2026-48548

## What is CVE-2026-48548?

CVE-2026-48548 is a medium-severity vulnerability in Nagios Core, published on 26 Aug 2026. 

### Official description

Nagios Core before 4.5.12 contains a cross-site request forgery vulnerability in cmd.cgi where the CSRF protection mechanism passes validation when the NagFormId cookie is absent. Attackers can craft a malicious cross-site POST request to execute arbitrary Nagios commands as a currently authenticated user without their knowledge or consent.

Weakness: CWE-352 (Cross-Site Request Forgery)

## Which versions are affected by CVE-2026-48548?


## How do I fix CVE-2026-48548?

Upgrade to a fixed version.

## Is CVE-2026-48548 being exploited?

There is no known exploitation of CVE-2026-48548 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-48548 and fix it if it is affected.

What it is: CVE-2026-48548 is a medium-severity vulnerability in Nagios Core, published on 26 Aug 2026. 
Exploitation: There is no known exploitation of CVE-2026-48548 in the wild and no public exploit code.

Affected product: Nagios Core. 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-2026-48548/ (Markdown: https://insights.sbomify.com/CVE-2026-48548/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-48548
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-48548
- OSV: https://osv.dev/vulnerability/CVE-2026-48548

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-48548/
Summaries are generated and may contain mistakes; the official description above is the record.