CVE-2026-84132

Analyzed Analyzed - Analysis Complete

Information Disclosure in Firefox Networking HTTP Component

Publication date: 2026-09-01

Last updated on: 2026-09-03

Assigner: Mozilla Corporation

Description

Information disclosure in the Networking: HTTP component. This vulnerability was fixed in Firefox 155, Firefox ESR 153.2, Thunderbird 155, and Thunderbird 153.2.

CVSS Scores

EPSS Scores

Probability:
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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-2026-84132

EUVD

EUVD-2026-69080

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 is an information disclosure vulnerability in the Networking: HTTP component of Firefox and Firefox ESR. It was patched in Firefox 155 and Firefox ESR 153.2.

Detection Guidance

This vulnerability is specific to Firefox versions before 155 and Firefox ESR before 153.2. To detect it, check your installed Firefox version using commands like 'firefox --version' or 'apt show firefox' on Linux. If the version is below 155 or ESR below 153.2, the system is vulnerable.

Impact Analysis

An attacker could exploit this to access sensitive information transmitted over HTTP, potentially exposing data like credentials or session tokens.

Compliance Impact

This vulnerability could lead to unauthorized data exposure, violating GDPR's data protection principles or HIPAA's safeguards for protected health information.

Mitigation Strategies

Update Firefox to version 155 or later and Firefox ESR to version 153.2 or later to address the information disclosure vulnerability.

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