# CVE-2026-119742: Nagios XI < 2026R2 OS Command Injection via mibs.php


- **Severity:** High 8.6 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 3 Nov 2026
- **Updated:** 3 Nov 2026
- **Also known as:** GHSA-xgjr-r6p2-hvm3, UBUNTU-CVE-2026-119742

## What is CVE-2026-119742?

CVE-2026-119742 is a high-severity vulnerability in Nagios XI, published on 3 Nov 2026. 

### Official description

Nagios XI before 2026R2 contains an OS command injection vulnerability in the MIB upload feature where the install_mib() function in mibs.php sanitizes uploaded filenames with an incomplete character-substitution filter that omits semicolons, pipes, and non-space IFS whitespace characters before passing them to a grep command run via exec(). An authenticated administrator can upload a MIB file with a crafted filename using tab characters to bypass the deny-list and pipe to sh via a multipart POST request to mibs.php, resulting in arbitrary OS command execution as the web server user.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command)

## Which versions are affected by CVE-2026-119742?


## How do I fix CVE-2026-119742?

No fix has been published for CVE-2026-119742 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-119742 being exploited?

There is no known exploitation of CVE-2026-119742 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-119742 and fix it if it is affected.

What it is: CVE-2026-119742 is a high-severity vulnerability in Nagios XI, published on 3 Nov 2026. 
Exploitation: There is no known exploitation of CVE-2026-119742 in the wild and no public exploit code.

Affected product: Nagios XI. 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-2026-119742/ (Markdown: https://insights.sbomify.com/CVE-2026-119742/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-119742
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-119742
- OSV: https://osv.dev/vulnerability/CVE-2026-119742

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-119742/
Summaries are generated and may contain mistakes; the official description above is the record.