Unauthenticated Arbitrary File Upload (upgrade_contents.php)

published 2025-11-26 11 mo ago modified 2026-10-18 21 d ago also EUVD-2025-199677

cvss: 9.8; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 35%
public exploits: 0; none known

Unauthenticated Arbitrary File Upload (upgrade_contents.php) 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 Missing signature validation allows uploading malicious firmware packages. The firmware upgrade endpoint in `upgrade_contents.php` accepts arbitrary file uploads without validating file headers, cryptographic signatures, or enforcing .tgz format requirements, allowing malicious firmware injection. This endpoint also subsequently provides ways for arbitrary file uploads and subsequent remote code execution

CISA SSVC

Exploitation: Proof of concept is public
Automatable: yes
Technical impact: total
Assessed: 11 mo ago (2025-12-03)

Exploit prediction

0.41% chance of exploitation in the next 30 days, higher than 35% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

abdulmhsblog.com https://www.abdulmhsblog.com/posts/webfmvulns/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	9.9	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:H/SI:N/SA:N
CNA	4.0	9.9	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

DB Electronica Telecomunicazioni S.p.A. Mozart FM Transmitter

Classification

Weakness

CWE-345 Insufficient Verification of Data Authenticity
CWE-434 Unrestricted Upload of File with Dangerous Type

References

abdulmhsblog.com /posts/webfmvulns/
exploit, technical-description, third-party-advisory

Sources

CVE List CVE-2025-66255
NVD CVE-2025-66255

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary