Description
Sandbox escape due to use-after-free in the Networking component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
Published: 2026-10-13
Score: 9.6 Critical
EPSS: n/a
KEV: No
Impact: Sandbox escape
Action: Immediate Patch
AI Analysis

Impact

A use‑after‑free bug in Firefox’s Networking component allows a maliciously crafted web page or network request to escape the browser’s sandbox. The flaw can lead to the execution of arbitrary code with privileges greater than the normal browser user context, potentially compromising the client system. This weakness corresponds to the Common Weakness Enumeration entry CWE‑416.

Affected Systems

Mozilla Firefox is affected when running versions older than 158, and the extended support release version 153.5 and earlier. The patch was applied in Firefox 158 and Firefox ESR 153.5, so any system using earlier releases is vulnerable.

Risk and Exploitability

The vulnerability lacks an EPSS score and is not listed in the CISA KEV catalog at this time, but its nature – a sandbox escape via use‑after‑free – indicates a high‑risk impact if exploited. Attackers would need to supply malicious content that triggers the abnormal memory access; no additional configuration is required beyond normal browsing behavior.

Generated by OpenCVE AI on October 13, 2026 at 15:43 UTC.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Update Firefox to version 158 or later, or the ESR 153.5 update, which contain the fix.
  • If an update cannot be applied immediately, monitor for security advisories and apply the update as soon as possible.
  • Apply network filtering or a firewall rule to block potentially untrusted traffic from unverified sources until the patch is available.

Generated by OpenCVE AI on October 13, 2026 at 15:43 UTC.

Tracking

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Advisories

No advisories yet.

History

Tue, 13 Oct 2026 18:30:00 +0000

Type Values Removed Values Added
Description Sandbox escape due to use-after-free in the Networking component. This vulnerability was fixed in Firefox 158 and Firefox ESR 153.5. Sandbox escape due to use-after-free in the Networking component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
References

Tue, 13 Oct 2026 16:15:00 +0000

Type Values Removed Values Added
First Time appeared Mozilla
Mozilla firefox
Vendors & Products Mozilla
Mozilla firefox

Tue, 13 Oct 2026 15:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-416
Metrics cvssV3_1

{'score': 9.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H'}

Tue, 13 Oct 2026 13:00:00 +0000

Type Values Removed Values Added
Description Sandbox escape due to use-after-free in the Networking component. This vulnerability was fixed in Firefox 158 and Firefox ESR 153.5.
Title Sandbox escape due to use-after-free in the Networking component
References

Subscriptions

Mozilla Firefox
cve-icon MITRE

Status: PUBLISHED

Assigner: mozilla

Published:

Updated: 2026-10-13T18:16:47.895Z

Reserved: 2026-10-13T00:29:16.501Z

Link: CVE-2026-109707

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-10-13T13:17:20.803

Modified: 2026-10-13T16:18:13.247

Link: CVE-2026-109707

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-13T16:00:13Z

Weaknesses