CVE-2026-109709

Deferred Deferred - Pending Action

Security Process Sandboxing Information Disclosure and Privilege Escalation in Firefox

Publication date: 2026-10-13

Last updated on: 2026-10-14

Assigner: Mozilla Corporation

Description

Information disclosure, privilege escalation in the Security: Process Sandboxing component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-10-13

Last Modified

2026-10-14

Generated

2026-10-19

AI Q&A

2026-10-13

EPSS Evaluated

2026-10-18

NVD

CVE-2026-109709

EUVD

EUVD-2026-98486

Affected Vendors & Products

Vendor	Product	Version / Range
mozilla	firefox	158
mozilla	firefox_esr	153.5
mozilla	firefox	to 158 (inc)
mozilla	firefox_esr	to 153.5 (inc)

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 involves information disclosure and privilege escalation in the Security: Process Sandboxing component of Firefox and Firefox ESR. It was addressed in Firefox 158 and Firefox ESR 153.5.

Detection Guidance

To detect this vulnerability, check the installed version of Firefox or Firefox ESR. Compare it against the fixed versions (Firefox 158 or Firefox ESR 153.5). Use commands like 'firefox --version' or 'firefox-esr --version' to verify the version.

Impact Analysis

An attacker could exploit this to gain elevated privileges or access sensitive information, potentially compromising user data or system integrity.

Compliance Impact

The vulnerability involves information disclosure and privilege escalation in Firefox's Security: Process Sandboxing component. This could lead to unauthorized access to sensitive data, which may violate GDPR's data protection requirements and HIPAA's safeguards for protected health information if exploited.

Mitigation Strategies

Update Firefox to version 158 or later and Firefox ESR to version 153.5 or later. This can be done through the application's built-in update mechanism or your system's package manager.

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