Focus v<138: URL Truncation Spoofing in Location Bar
CVE-2025-3859 Published on April 30, 2025

Firefox Focus elide URL allows address bar spoofing
Websites directing users to long URLs that caused eliding to occur in the location view could leverage the truncating behavior to potentially trick users into thinking they were on a different webpage. This vulnerability was fixed in Focus 138.

NVD

Vulnerability Analysis

CVE-2025-3859 can be exploited with network access, requires user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a small impact on confidentiality, a small impact on integrity and availability.

Exploitation:
NONE
Automatable:
NO
Technical Impact:
PARTIAL
Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
REQUIRED
Scope:
UNCHANGED
Confidentiality Impact:
LOW
Integrity Impact:
NONE
Availability Impact:
NONE

Weakness Type

User Interface (UI) Misrepresentation of Critical Information

The user interface (UI) does not properly represent critical information to the user, allowing the information - or its source - to be obscured or spoofed. This is often a component in phishing attacks.


Products Associated with CVE-2025-3859

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Mozilla Firefox Focus
Mozilla Focus

Affected Versions

Mozilla Focus:

Exploit Probability

EPSS
0.21%
Percentile
10.94%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.