CVE-2026-16391

Analyzed Analyzed - Analysis Complete

Information Disclosure in Firefox Storage IndexedDB

Publication date: 2026-07-21

Last updated on: 2026-07-24

Assigner: Mozilla Corporation

Description

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

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-07-21

Last Modified

2026-07-24

Generated

2026-08-11

AI Q&A

2026-07-21

EPSS Evaluated

2026-08-09

NVD

CVE-2026-16391

EUVD

EUVD-2026-46228

Affected Vendors & Products

Vendor	Product	Version / Range
mozilla	firefox	to 153.0.0 (exc)
mozilla	firefox	to 140.13.0 (exc)
mozilla	thunderbird	to 140.13.0 (exc)
mozilla	thunderbird	From 141.0 (inc) to 153.0 (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 Storage: IndexedDB component of Firefox. It allows unauthorized access to sensitive data stored in IndexedDB, which is a client-side storage mechanism used by web applications.

Detection Guidance

This vulnerability is specific to Firefox versions before 153 and Firefox ESR before 140.13. To detect it, check your Firefox version by running 'firefox --version' or 'about:support' in the browser. If your version is below the fixed releases, the system is vulnerable.

Impact Analysis

If exploited, this vulnerability could allow attackers to access private data stored in IndexedDB, such as user credentials, session tokens, or other sensitive information, potentially leading to identity theft or unauthorized account access.

Compliance Impact

This vulnerability could lead to non-compliance with GDPR or HIPAA if it results in unauthorized access to personal or health data. Organizations may face legal penalties, fines, or reputational damage due to data breaches caused by this issue.

Mitigation Strategies

Update Firefox to version 153 or later and Firefox ESR to version 140.13 or later to address the Information disclosure in Storage: IndexedDB vulnerability.

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