CVE-2026-84120
Received Received - Intake

Use-after-free in Firefox Audio/Video Component

Publication date: 2026-09-01

Last updated on: 2026-09-01

Assigner: Mozilla Corporation

Description
Use-after-free in the Audio/Video component. This vulnerability was fixed in Firefox 155, Firefox ESR 115.40, Firefox ESR 140.15, and Firefox ESR 153.2.

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Meta Information

Published
2026-09-01
Last Modified
2026-09-01
Generated
2026-09-01
AI Q&A
2026-09-01
EPSS Evaluated
N/A
NVD
CVE-2026-84120
EUVD
EUVD-2026-69065

Affected Vendors & Products

Showing 8 associated CPEs
Vendor Product Version / Range
mozilla firefox to 155 (inc)
mozilla firefox_esr to 115.40 (inc)
mozilla firefox_esr to 140.15 (inc)
mozilla firefox_esr to 153.2 (inc)
mozilla firefox 155
mozilla firefox_esr 115.40
mozilla firefox_esr 140.15
mozilla firefox_esr 153.2

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-416 The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

Attack-Flow Graph

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Executive Summary

This is a use-after-free vulnerability in Firefox's Audio/Video component. Use-after-free occurs when a program continues to use memory after it has been freed, potentially leading to crashes or arbitrary code execution.

Detection Guidance

This vulnerability is fixed in Firefox 155, Firefox ESR 115.40, Firefox ESR 140.15, and Firefox ESR 153.2. Check your Firefox version with 'firefox --version' or 'about:support' in Firefox. If your version is older, update immediately.

Impact Analysis

An attacker could exploit this to crash your browser or run malicious code on your device. This could lead to data theft, system compromise, or installation of malware if you visit a specially crafted website.

Compliance Impact

The vulnerability is a use-after-free in Firefox's Audio/Video component, which could allow attackers to execute arbitrary code or bypass security restrictions. This type of flaw may lead to unauthorized data access or processing, potentially violating GDPR's data protection requirements or HIPAA's safeguards for protected health information if exploited.

Mitigation Strategies

Update Firefox to version 155 or later, Firefox ESR 115.40 or later, Firefox ESR 140.15 or later, or Firefox ESR 153.2 or later to address the use-after-free vulnerability in the Audio/Video component.

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