Mozart FM Transmitter: Improper Neutralization of Null Byte or NUL Character
CVE-2025-66263 is a high-severity improper neutralization of null byte or NUL character vulnerability in Mozart FM Transmitter from DB Electronica Telecomunicazioni S.p.A., with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Mozart FM Transmitter versions: 30; 50; 100, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.42% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Mozart FM Transmitter you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| DB Electronica Telecomunicazioni S.p.A. | Mozart FM Transmitter | 30; 50; 100; 300; 500; 1000; 2000; 3000; and 3 more ranges | Not stated |
| Dbbroadcast | Mozart Next 3000 Firmware | Not specified in the record | Not stated |
| Dbbroadcast | Mozart Next 3500 Firmware | Not specified in the record | Not stated |
| Dbbroadcast | Mozart Next 50 Firmware | Not specified in the record | Not stated |
| Dbbroadcast | Mozart Next 500 Firmware | Not specified in the record | Not stated |
| Dbbroadcast | Mozart Next 6000 Firmware | Not specified in the record | Not stated |
| Dbbroadcast | Mozart Next 7000 Firmware | Not specified in the record | Not stated |
| Dbbroadcast | Mozart Next 100 Firmware | Not specified in the record | Not stated |
| Dbbroadcast | Mozart Next 1000 Firmware | Not specified in the record | Not stated |
| Dbbroadcast | Mozart Next 2000 Firmware | Not specified in the record | Not stated |
| Dbbroadcast | Mozart Next 30 Firmware | Not specified in the record | Not stated |
| Dbbroadcast | Mozart Next 300 Firmware | Not specified in the record | Not stated |
| Dbbroadcast | Mozart Dds Next 30 Firmware | Not specified in the record | Not stated |
| Dbbroadcast | Mozart Dds Next 50 Firmware | Not specified in the record | Not stated |
| Dbbroadcast | Mozart Dds Next 100 Firmware | Not specified in the record | Not stated |
| Dbbroadcast | Mozart Dds Next 300 Firmware | Not specified in the record | Not stated |
| Dbbroadcast | Mozart Dds Next 500 Firmware | Not specified in the record | Not stated |
| Dbbroadcast | Mozart Dds Next 1000 Firmware | Not specified in the record | Not stated |
| Dbbroadcast | Mozart Dds Next 2000 Firmware | Not specified in the record | Not stated |
| Dbbroadcast | Mozart Dds Next 3000 Firmware | Not specified in the record | Not stated |
| Dbbroadcast | Mozart Dds Next 3500 Firmware | Not specified in the record | Not stated |
| Dbbroadcast | Mozart Dds Next 6000 Firmware | Not specified in the record | Not stated |
| Dbbroadcast | Mozart Dds Next 7000 Firmware | Not specified in the record | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.9 | High | CNA |
| CVSS 3.1 | 7.5 | High | NVD |
Official description
Unauthenticated Arbitrary File Read via Null Byte Injection in DB Electronica Telecomunicazioni S.p.A. Mozart FM Transmitter versions 30, 50, 100, 300, 500, 1000, 2000, 3000, 3500, 6000, 7000 allows an attacker to perform Null byte injection in download_setting.php allows reading arbitrary files. The `/var/tdf/download_setting.php` endpoint constructs file paths by concatenating user-controlled `$_GET['filename']` with a forced `.tgz` extension. Running on PHP 5.3.2 (pre-5.3.4), the application is vulnerable to null byte injection (%00), allowing attackers to bypass the extension restriction and traverse paths. By requesting `filename=../../../../etc/passwd%00`, the underlying C functions treat the null byte as a string terminator, ignoring the appended `.tgz` and enabling unauthenticated arbitrary file disclosure of any file readable by the web server user.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Null Byte or NUL Character
The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes NUL characters or null bytes when they are sent to a downstream component.
How developers prevent this class of flaw
- Developers should anticipate that null characters or null bytes will be injected/removed/manipulated in the input vectors of their product. Use an appropriate combination of denylists and allowlists to ensure only valid, expected and appropriate input is processed by the system.
- Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.
More Improper Neutralization of Null Byte or NUL Character vulnerabilities (CWE-158)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Technical write-ups (may include proof of concept)
- abdulmhsblog.com/posts/webfmvulns/Exploit, Third Party Advisory
Other vulnerabilities in Mozart FM Transmitter
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.1 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
Recent Improper Neutralization of Null Byte or NUL Character vulnerabilities
- 8.7 High severity
- 10.0 Critical severity
- 10.0 Critical severity
- 7.3 High severity
- 8.1 High severity
- 9.8 Critical severity
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