How to fix CVE-2025-1935?

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Verify Content-Security-Policy and output encoding.

Is Firefox affected by CVE-2025-1935?

CVE-2025-1935 presents moderate security risk, a cross-site scripting vulnerability rated CVSS 4.3. Attackers could inject scripts to steal sessions or perform actions as authenticated users. Organizations should apply vendor updates when available and monitor for exploitation.

CVE-2025-1935

MEDIUM

2025-03-04 [email protected]

4.3

CVSS 3.1

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

None

Lifecycle Timeline

Patch Released

Apr 05, 2026 - 02:30 nvd

Patch available

Analysis Generated

Mar 28, 2026 - 18:29 vuln.today

CVE Published

Mar 04, 2025 - 14:15 nvd

MEDIUM 4.3

Description

A web page could trick a user into setting that site as the default handler for a custom URL protocol. This vulnerability affects Firefox < 136, Firefox ESR < 128.8, Thunderbird < 136, and Thunderbird < 128.8.

Analysis

A web page could trick a user into setting that site as the default handler for a custom URL protocol. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

Technical Context

This vulnerability is classified as Cross-Site Scripting (XSS) (CWE-79), which allows attackers to inject malicious scripts into web pages viewed by other users. A web page could trick a user into setting that site as the default handler for a custom URL protocol. This vulnerability affects Firefox < 136, Firefox ESR < 128.8, Thunderbird < 136, and Thunderbird < 128.8. Affected products include: Mozilla Firefox, Mozilla Thunderbird.

Affected Products

Mozilla Firefox, Mozilla Thunderbird.

Remediation

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Sanitize all user input, use Content-Security-Policy headers, encode output contextually (HTML, JS, URL). Use frameworks with built-in XSS protection.

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +0.3

CVSS: +22

POC: 0

Vendor Status

CVE-2025-1935 vulnerability details – vuln.today

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CVE-2025-1935

CVSS Vector

Lifecycle Timeline

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Analysis

Technical Context

Affected Products

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CVE-2025-1935

CVSS Vector

Lifecycle Timeline

Tags

Description

Analysis

Technical Context

Affected Products

Remediation

Priority Score

Vendor Status

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External POC / Exploit Code