OS Command Injection Affecting fastnetmon package, versions *


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
1.65% (74th percentile)

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  • Snyk IDSNYK-UBUNTU2510-FASTNETMON-16913705
  • published12 Jun 2026
  • disclosed26 May 2026

Introduced: 26 May 2026

CVE-2026-48687  (opens in a new tab)
CWE-78  (opens in a new tab)

How to fix?

There is no fixed version for Ubuntu:25.10 fastnetmon.

NVD Description

Note: Versions mentioned in the description apply only to the upstream fastnetmon package and not the fastnetmon package as distributed by Ubuntu. See How to fix? for Ubuntu:25.10 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1