CVE-2026-16383 is a mitigation bypass vulnerability affecting the DOM: Networking component in Mozilla Firefox. It was reported by Ibuki Sato and Tomoya Nakanishi and is classified with moderate impact. The vulnerability was fixed in Firefox 153 and Firefox ESR 140.13 as part of a comprehensive security update addressing numerous vulnerabilities. The vendor advisory does not provide detailed technical exploitation methods but confirms the fix availability in these versions. No active exploitation in the wild has been observed.

The vulnerability allows bypassing mitigation mechanisms in the DOM: Networking component, potentially undermining security controls within Firefox. While the impact is rated moderate, it could facilitate further attacks if combined with other vulnerabilities. No evidence of exploitation in the wild has been reported, reducing immediate risk. However, the presence of this flaw could weaken the browser's defense against certain attack vectors related to DOM networking operations.

Mozilla has released official fixes for this vulnerability in Firefox 153 and Firefox ESR 140.13. Users and administrators should update to these versions or later to remediate the issue. Since the vulnerability is fixed in these releases, no additional mitigation steps are required beyond applying the official update. Patch status is confirmed by the vendor advisory.