Vulnerability Details CVE-2026-48687
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.005
EPSS Ranking 67.4%
CVSS Severity
CVSS v3 Score 9.8
Products affected by CVE-2026-48687
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cpe:2.3:a:pavel-odintsov:fastnetmon:1.0.0
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cpe:2.3:a:pavel-odintsov:fastnetmon:1.1.0
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cpe:2.3:a:pavel-odintsov:fastnetmon:1.1.1
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cpe:2.3:a:pavel-odintsov:fastnetmon:1.1.2
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cpe:2.3:a:pavel-odintsov:fastnetmon:1.1.3
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cpe:2.3:a:pavel-odintsov:fastnetmon:1.1.4
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cpe:2.3:a:pavel-odintsov:fastnetmon:1.1.5
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cpe:2.3:a:pavel-odintsov:fastnetmon:1.1.6
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cpe:2.3:a:pavel-odintsov:fastnetmon:1.1.7
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cpe:2.3:a:pavel-odintsov:fastnetmon:1.1.8
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cpe:2.3:a:pavel-odintsov:fastnetmon:1.1.9
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cpe:2.3:a:pavel-odintsov:fastnetmon:1.2.0
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cpe:2.3:a:pavel-odintsov:fastnetmon:1.2.1
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cpe:2.3:a:pavel-odintsov:fastnetmon:1.2.2
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cpe:2.3:a:pavel-odintsov:fastnetmon:1.2.3
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cpe:2.3:a:pavel-odintsov:fastnetmon:1.2.4
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cpe:2.3:a:pavel-odintsov:fastnetmon:1.2.5
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cpe:2.3:a:pavel-odintsov:fastnetmon:1.2.6
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cpe:2.3:a:pavel-odintsov:fastnetmon:1.2.7
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cpe:2.3:a:pavel-odintsov:fastnetmon:1.2.8