CVE-2026-48687

OS Command Injection in FastNetMon Juniper Plugin

Published May 26, 2026 CVSS 3.1 · 8.1 High EPSS 1.6% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DSA Debian DSA DSA-6375-1 fastnetmon security update
History
Type Values Removed Values Added
Title OS Command Injection in FastNetMon Juniper Plugin
Type Values Removed Values Added
Title OS Command Injection in FastNetMon Juniper Plugin
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N'}

Type Values Removed Values Added
CPEs cpe:2.3:a:pavel-odintsov:fastnetmon:*:*:*:*:community:*:*:*
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

Type Values Removed Values Added
Title OS Command Injection in FastNetMon Juniper Plugin
First Time appeared Pavel-odintsov
Pavel-odintsov fastnetmon
Weaknesses CWE-78
Vendors & Products Pavel-odintsov
Pavel-odintsov fastnetmon
Type Values Removed Values Added
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.
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
mitre
Published
Updated
May 27, 2026, 5:23 PM
Reserved
May 22, 2026, 12:00 AM
Status
Modified
Published
May 26, 2026, 4:16 PM
Modified
Jul 21, 2026, 7:10 PM