CVE-2026-109705
Deferred Deferred - Pending Action

Firefox Networking Component Use-After-Free Vulnerability

Publication date: 2026-10-13

Last updated on: 2026-10-13

Assigner: Mozilla Corporation

Description
Sandbox escape, site isolation issue due to incorrect boundary conditions, use-after-free in the Networking component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-10-13
Last Modified
2026-10-13
Generated
2026-10-19
AI Q&A
2026-10-13
EPSS Evaluated
2026-10-18
NVD
CVE-2026-109705
EUVD
EUVD-2026-98483

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
mozilla firefox 158
mozilla firefox_esr 153.5

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.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

AI Quick Actions

Instant insights powered by AI
Executive Summary

This is a sandbox escape vulnerability in Firefox caused by incorrect boundary conditions and a use-after-free issue in the Networking component. It allows malicious code to break out of the browser's security sandbox, potentially accessing system resources or other browser data.

Detection Guidance

This vulnerability was fixed in Firefox 158 and Firefox ESR 153.5. To detect if your system is vulnerable, check the installed Firefox version using the command: firefox --version. If the version is below 158 (or 153.5 for ESR), the system is vulnerable.

Impact Analysis

If exploited, this vulnerability could allow an attacker to run arbitrary code on your system, steal sensitive data, or perform actions outside the browser's security restrictions. Users of affected Firefox versions are at risk until they update to Firefox 158 or Firefox ESR 153.5.

Compliance Impact

This vulnerability could potentially lead to unauthorized access to sensitive data due to sandbox escape and use-after-free issues, which may violate data protection requirements under GDPR and HIPAA. The high CVSS score indicates a significant risk of confidentiality, integrity, and availability breaches.

Mitigation Strategies

Update Firefox to version 158 or later and Firefox ESR to version 153.5 or later to patch the vulnerability.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-109705. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart