CVE-2026-84134

Analyzed Analyzed - Analysis Complete

Firefox 155 and Firefox ESR 153.2 Profile Backup Component Vulnerability

Publication date: 2026-09-01

Last updated on: 2026-09-03

Assigner: Mozilla Corporation

Description

Other issue in the Profile Backup component. This vulnerability was fixed in Firefox 155, Firefox ESR 153.2, Thunderbird 155, and Thunderbird 153.2.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-09-01

Last Modified

2026-09-03

Generated

2026-09-21

AI Q&A

2026-09-01

EPSS Evaluated

2026-09-20

NVD

CVE-2026-84134

EUVD

EUVD-2026-69082

Affected Vendors & Products

Vendor	Product	Version / Range
mozilla	firefox	to 153.2.0 (exc)
mozilla	firefox	From 154.0.0 (inc) to 155.0.0 (exc)
mozilla	thunderbird	to 153.2.0 (exc)
mozilla	thunderbird	From 154.0 (inc) to 155.0 (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 in the Profile Backup component of Firefox and Firefox ESR. It was addressed in Firefox 155 and Firefox ESR 153.2.

Detection Guidance

This vulnerability is specific to Firefox 155 and Firefox ESR 153.2. To detect it, check your installed Firefox version using commands like 'firefox --version' or 'about:support' in Firefox. If you are running an affected version, update to the latest patched version immediately.

Impact Analysis

The impact is not specified in the provided context. Users should update to Firefox 155 or Firefox ESR 153.2 to mitigate potential risks.

Compliance Impact

The provided CVE data does not specify any impact on compliance with standards like GDPR or HIPAA. The vulnerability is described as an issue in the Profile Backup component fixed in Firefox 155 and Firefox ESR 153.2, but no details are given about data exposure or regulatory implications.

Mitigation Strategies

Update Firefox to version 155 or later and Firefox ESR to version 153.2 or later to address the Profile Backup component vulnerability.

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