CVE-2025-66253 is a critical (CVSS 9.8) unauthenticated OS command injection in the Mozart FM Transmitter. The start_upgrade.php endpoint passes a filename request parameter straight into exec() without sanitization. Anyone who can reach the page may run commands on the device. The record names no fix, so isolate the interface and contact the vendor.
What's affected
- Product: Mozart FM Transmitter from DB Electronica Telecomunicazioni S.p.A. (DB Broadcast), web management interface. The record lists models 30, 50, 100, 300, 500, 1000, 2000, 3000, 3500, 6000 and 7000.
- Component: /var/tdf/start_upgrade.php and its filename parameter, which is passed into a shell command.
- Fixed: neither the record nor the researcher write-up we read names a fixed firmware version or a vendor advisory. Contact the vendor for patch status before assuming one exists.
- Severity: the record scores it 9.8 (critical) with the vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. The record says commands run as the web server user, which it describes as likely root. That is why the rating is critical with high impact across the board.
How to check if you're exposed
This is a broadcast appliance, so there is no package manager to query. Work from the device and the network.
- Build a list of every Mozart unit you run, with its model and the web interface version string. The researcher write-up refers to the web management interface version WEBMOZZI-00287.
- Find out whether the management web interface of each unit is reachable from the internet, from a partner network or from a flat internal network. Check firewall rules and any remote access gateway.
- Look at the web server logs on a device you can inspect, or at the logs of any proxy in front of it, for requests to the PHP file named in this CVE from addresses you do not recognize.
If the interface is reachable by people outside the small group that needs it, treat the device as exposed.
What to do now
- Take the management interface off the internet and off any shared network. Put it behind a VPN or a jump host, with an allow list of administrator addresses.
- Ask DB Broadcast for the patch status of this CVE and for a firmware version that fixes it. Record the answer with your asset notes.
- If the device was exposed, plan for a clean reinstall from a trusted image after the vendor provides one, since a root level compromise is hard to rule out by inspection.
- Watch the device for unexpected files, new accounts, changed settings or reboots, and keep a known good copy of its configuration to compare against.
- Add the rest of your internet facing software to an inventory. Safeguard cannot patch a transmitter, but a free in-browser scan at gold.safeguard.sh/scan and a proper asset inventory help you find the other internet facing software you run, and reachability analysis helps you rank what to fix first.
Why it matters
The weakness is CWE-78, OS command injection. The record explains that user controlled input goes directly into exec() with no shell escaping, so shell metacharacters in the input are treated as new commands. We leave out the specifics, since the point for defenders is the class of mistake, not the way to use it.
Command injection on an unauthenticated page is about as severe as web flaws get, and on an appliance that runs as a privileged user it means full control of the device. Safe code passes arguments to a program as a list and validates a filename against a known set, instead of building a command string. The record does not mark this as exploited in the wild and it is not on the CISA KEV list. The advisory trail is thin, since the main public source is a researcher write-up rather than a vendor bulletin, so confirm facts with the vendor. Appliances of this kind sit for years without updates, which is why network isolation is the control you can apply today.
Quick check
Is a login required?
No. The record calls this unauthenticated.
What privileges do the commands run with?
The record says the web server user, likely root.
Sources
- Researcher write-up: 14 vulnerabilities in the Mozart FM Transmitter web interface
- Safeguard Gold entry
Last reviewed: 18 October 2026.
