CVE-2026-48687 Command injection in n/a
Attackers can execute arbitrary OS commands via unsanitized input in the Juniper router integration plugin of FastNetMon Community Edition.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-48687?
CVE-2026-48687 is a high-severity command injection vulnerability in n/a, published on 26 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-78
Which versions are affected by CVE-2026-48687?
It affects 1 product.
Products include Pavel-Odintsov Fastnetmon.
How do I fix CVE-2026-48687?
Apply the vendor's patch.
Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.
Is CVE-2026-48687 being exploited?
There is no known exploitation of CVE-2026-48687 in the wild and no public exploit code.
Other vulnerabilities in n/a
Sources
Also known as DEBIAN-CVE-2026-48687, GHSA-qx97-6jw5-h44w, UBUNTU-CVE-2026-48687.