OS Command Injection Affecting fastnetmon package, versions <1.2.9-0+deb13u1


Severity

Recommended
0.0
critical
0
10

Snyk's Security Team recommends NVD's CVSS assessment. Learn more

Threat Intelligence

EPSS
1.65% (77th percentile)

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  • Snyk IDSNYK-ECHOLATEST-FASTNETMON-17978350
  • published15 Jul 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?

Upgrade Echo:latest fastnetmon to version 1.2.9-0+deb13u1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream fastnetmon package and not the fastnetmon package as distributed by Echo. See How to fix? for Echo:latest 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 &#34;- {FASTNETMON] - " . $msg . " &#34; >> " . $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