CVE-2026-16353 -- CVSS 9.8 Vulnerability Briefing

CVE-2026-16353 | CVSS 9.8 (Critical) | Exploit: No known exploit

What Is It

CVE-2026-16353 is an invalid-pointer vulnerability in Mozilla Firefox and Thunderbird within the DOM Bindings (WebIDL) component, which processes web-exposed interface bindings.

Technical Detail

The flaw involves invalid pointer handling in DOM Bindings (WebIDL), creating a memory-safety condition when affected applications process crafted web content. An attacker could potentially trigger the issue by causing a user to load malicious web content in Firefox or content rendered by Thunderbird. Successful exploitation could result in arbitrary code execution in the context of the affected application, subject to platform protections and additional exploit requirements.

Exploitation Status

No known exploit has been reported. CVE-2026-16353 is not listed in CISA's Known Exploited Vulnerabilities catalog as of July 28, 2026.

Who Is Targeting This

No specific threat actor attribution at this time.

What To Do

Prioritize updates to Firefox 153 or later, Firefox ESR 115.38 or later, Firefox ESR 140.13 or later, Thunderbird 153 or later, and Thunderbird 140.13 or later. Verify that managed endpoints have received the applicable vendor update and restart affected applications where required to load the patched binaries. No workaround, detection indicators, or confirmed exploitation activity has been provided for this vulnerability; until patch deployment is complete, reduce exposure to untrusted web content and suspicious links or attachments that may cause Firefox or Thunderbird to render attacker-controlled content.