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.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | fastnetmon | 1.2.9-1 | — |
| Debian 13 | fastnetmon | 1.2.9-0+deb13u1 | — |
| Debian 12 | fastnetmon | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | fastnetmon | No fix yet | — |
| Ubuntu 25.10 | fastnetmon | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 26.04 LTS | fastnetmon | 1.2.8+git20250911-2ubuntu0.1~esm1 | USN-8429-1 |
| Ubuntu Pro 24.04 LTS | fastnetmon | 1.2.6-1ubuntu0.1~esm1 | USN-8429-1 |
| Ubuntu Pro 20.04 LTS | fastnetmon | 1.1.4-1ubuntu0.1~esm1 | USN-8429-1 |
Advisories 1
- USN-8429-1 fastnetmon vulnerabilities Ubuntu Security Notices (USN) · Jun 16, 2026