# CVE-2026-48687: Command injection in n/a

> Attackers can execute arbitrary OS commands via unsanitized input in the Juniper router integration plugin of FastNetMon Community Edition.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 26 May 2026
- **Updated:** 27 May 2026
- **Also known as:** DEBIAN-CVE-2026-48687, GHSA-qx97-6jw5-h44w, UBUNTU-CVE-2026-48687

## What is CVE-2026-48687?

CVE-2026-48687 is a high-severity command injection vulnerability in n/a, published on 26 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

FastNetMon Community Edition through 1.2.9 contains an OS command injection vulnerability in the Juniper router integration plugin. The _log() function in src/juniper_plugin/fastnetmon_juniper.php (lines 117-118) constructs shell commands by concatenating the $msg parameter directly into exec() calls: exec("echo `date` \"- {FASTNETMON] - " . $msg . " \" >> " . $FILE_LOG_TMP). The $msg variable contains unsanitized data derived from command-line arguments argv[1] through argv[3], which represent the attack IP address, direction, and power. While FastNetMon's C++ core currently passes IP addresses via inet_ntoa() (which only produces safe dotted-decimal notation), the PHP script performs no input validation or shell escaping. If the script is invoked directly, by another orchestration system, or if future code changes pass string-sourced IPs, arbitrary commands can be injected. The correct fix is to replace exec() with file_put_contents() or use escapeshellarg() on all parameters.

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

## Which versions are affected by CVE-2026-48687?

It affects 1 product.


Products: Pavel-Odintsov Fastnetmon.

## How do I fix CVE-2026-48687?

Apply the vendor's patch.

## Is CVE-2026-48687 being exploited?

There is no known exploitation of CVE-2026-48687 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2026-48686](https://insights.sbomify.com/CVE-2026-48686/): Memory corruption in n/a (critical 9.8)
- [CVE-2026-48689](https://insights.sbomify.com/CVE-2026-48689/): Memory corruption in n/a (critical 9.8)
- [CVE-2026-48692](https://insights.sbomify.com/CVE-2026-48692/): Missing authorization in n/a (high 8.1)
- [CVE-2026-48694](https://insights.sbomify.com/CVE-2026-48694/): Command injection in n/a (high 8.1)
- [CVE-2026-48695](https://insights.sbomify.com/CVE-2026-48695/): Command injection in n/a (high 8.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-48687 and fix it if it is affected.

What it is: CVE-2026-48687 is a high-severity command injection vulnerability in n/a, published on 26 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-48687 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-2026-48687/ (Markdown: https://insights.sbomify.com/CVE-2026-48687/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-48687
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-48687
- OSV: https://osv.dev/vulnerability/CVE-2026-48687

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-48687/
Summaries are generated and may contain mistakes; the official description above is the record.