CVE-2026-16356

Analyzed Analyzed - Analysis Complete

Sandbox Escape via Use-After-Free in Firefox

Publication date: 2026-07-21

Last updated on: 2026-07-24

Assigner: Mozilla Corporation

Description

Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability was fixed in Firefox 153, Firefox ESR 115.38, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-07-21

Last Modified

2026-07-24

Generated

2026-08-11

AI Q&A

2026-07-21

EPSS Evaluated

2026-08-09

NVD

CVE-2026-16356

EUVD

EUVD-2026-46204

Affected Vendors & Products

Vendor	Product	Version / Range
mozilla	firefox	to 153.0.0 (exc)
mozilla	firefox	to 115.38.0 (exc)
mozilla	firefox	From 128.1.0 (inc) to 140.13.0 (exc)
mozilla	thunderbird	to 140.13.0 (exc)
mozilla	thunderbird	From 141.0 (inc) to 153.0 (exc)

Helpful Resources

Exploitability

CWE

KEV

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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
CWE-693	The product does not use or incorrectly uses a protection mechanism that provides sufficient defense against directed attacks against the product.

Attack-Flow Graph

Executive Summary

This is a sandbox escape vulnerability caused by a use-after-free issue in the Disability Access APIs component of Firefox. A use-after-free occurs when a program continues to use memory after it has been freed, potentially allowing an attacker to execute arbitrary code or gain elevated privileges.

Detection Guidance

Detection requires checking Firefox version. Run 'firefox --version' or check 'about:support' in Firefox. If version is below 153, 115.38 (ESR), or 140.13 (ESR), the system is vulnerable.

Impact Analysis

This vulnerability could allow an attacker to escape the browser sandbox and execute code on your system with the same privileges as the browser. This could lead to data theft, installation of malware, or further compromise of your system.

Compliance Impact

The provided CVE data does not specify direct impacts on compliance with GDPR, HIPAA, or other standards. The vulnerability involves a sandbox escape due to use-after-free in Disability Access APIs, which could potentially allow unauthorized access to sensitive data. However, no explicit compliance implications are mentioned in the context.

Mitigation Strategies

Update Firefox to version 153 or later, Firefox ESR 115.38 or later, or Firefox ESR 140.13 or later. Disable Disability Access APIs if not needed via Firefox settings.

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