CVE-2026-84138

Modified Modified - Updated After Analysis

Denial-of-Service in Firefox PDF Viewer

Publication date: 2026-09-01

Last updated on: 2026-09-03

Assigner: Mozilla Corporation

Description

Denial-of-service in the PDF Viewer component. This vulnerability was fixed in Firefox 155 and Thunderbird 155.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-09-01

Last Modified

2026-09-03

Generated

2026-09-22

AI Q&A

2026-09-01

EPSS Evaluated

2026-09-21

NVD

CVE-2026-84138

EUVD

EUVD-2026-69086

Affected Vendors & Products

Vendor	Product	Version / Range
mozilla	firefox	to 155.0.0 (exc)
mozilla	thunderbird	to 155.0 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-400	The product does not properly control the allocation and maintenance of a limited resource.

Attack-Flow Graph

Executive Summary

This is a denial-of-service vulnerability in Firefox's PDF Viewer component. It allows an attacker to crash the application by exploiting a flaw in how it processes PDF files.

Detection Guidance

Detection methods or specific commands for this vulnerability are not provided in the available context. General detection would involve checking Firefox version against 155 or later and monitoring for unusual PDF viewer crashes or resource exhaustion.

Impact Analysis

If exploited, this vulnerability could cause Firefox to crash when viewing a malicious PDF file. This may lead to loss of unsaved work or disruption of services relying on the browser.

Compliance Impact

This vulnerability does not provide specific details about compliance impacts on standards like GDPR or HIPAA. The denial-of-service issue in the PDF Viewer component may disrupt service availability, which could indirectly affect compliance if systems fail to meet uptime or data access requirements.

Mitigation Strategies

Update Firefox to version 155 or later to address the denial-of-service vulnerability in the PDF Viewer component.

Hi! I’m here to help you understand CVE-2026-84138. Ask me anything about the vulnerability, its impact, or mitigation strategies.

0/70