CVE-2026-16405

Modified Modified - Updated After Analysis

Information Disclosure in Firefox WebSockets

Publication date: 2026-07-21

Last updated on: 2026-07-22

Assigner: Mozilla Corporation

Description

Information disclosure in the Networking: WebSockets component. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-07-21

Last Modified

2026-07-22

Generated

2026-08-11

AI Q&A

2026-07-21

EPSS Evaluated

2026-08-09

NVD

CVE-2026-16405

EUVD

EUVD-2026-46243

Affected Vendors & Products

Vendor	Product	Version / Range
mozilla	firefox	to 153.0.0 (exc)
mozilla	firefox	From 140.1.0 (inc) to 140.13.0 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-200	The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.

Attack-Flow Graph

Executive Summary

This vulnerability is an information disclosure issue in the Networking: WebSockets component of Firefox. It was patched in Firefox version 153 and Firefox ESR version 140.13.

Detection Guidance

This vulnerability affects the Networking: WebSockets component in Firefox and Firefox ESR. To detect it, check the installed version of Firefox or Firefox ESR on your system. If the version is below 153 for Firefox or 140.13 for Firefox ESR, the system is vulnerable.

Impact Analysis

An attacker could exploit this flaw to access sensitive information transmitted over WebSockets in Firefox. This may lead to unauthorized data exposure if the affected versions are used.

Compliance Impact

The provided CVE data does not specify the nature of the information disclosure or its impact on compliance standards like GDPR or HIPAA. Without details on what data is exposed or how it is handled, it is unclear how this vulnerability would affect compliance.

Mitigation Strategies

Update Firefox to version 153 or later and Firefox ESR to version 140.13 or later to address the information disclosure vulnerability in the WebSockets component.

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