CVE-2026-109716

Deferred Deferred - Pending Action

JavaScript Engine Boundary Condition Flaw in Firefox

Publication date: 2026-10-13

Last updated on: 2026-10-16

Assigner: Mozilla Corporation

Description

Incorrect boundary conditions in the JavaScript Engine component. This vulnerability was fixed in Firefox 158, Firefox ESR 115.43, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-10-13

Last Modified

2026-10-16

Generated

2026-10-19

AI Q&A

2026-10-13

EPSS Evaluated

2026-10-18

NVD

CVE-2026-109716

EUVD

EUVD-2026-98639

Affected Vendors & Products

Vendor	Product	Version / Range
mozilla	firefox	to 158 (inc)
mozilla	firefox_esr	to 115.43 (inc)
mozilla	firefox_esr	to 153.5 (inc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-119	The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.

Attack-Flow Graph

Executive Summary

This vulnerability involves incorrect boundary conditions in the JavaScript Engine component of Firefox browsers. It was addressed in Firefox 158 and specific Firefox ESR versions (115.43 and 153.5).

Detection Guidance

This vulnerability affects the JavaScript Engine in Firefox and Firefox ESR. To detect it, check your installed Firefox version against the fixed versions (Firefox 158, Firefox ESR 115.43, or Firefox ESR 153.5). Use commands like 'firefox --version' or 'apt show firefox' (Linux) to verify. If your version is older, the system is vulnerable.

Impact Analysis

The vulnerability could allow attackers to exploit boundary conditions, potentially leading to memory corruption, crashes, or arbitrary code execution in affected Firefox browsers.

Compliance Impact

The provided CVE data does not specify how this vulnerability affects compliance with standards like GDPR or HIPAA. The description only mentions incorrect boundary conditions in the JavaScript Engine component without detailing potential data exposure or privacy impacts.

Mitigation Strategies

Update Firefox to version 158 or later, Firefox ESR to version 115.43 or later, or Firefox ESR to version 153.5 or later to address the incorrect boundary conditions in the JavaScript Engine component.

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