CVE-2026-117925

A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue: Use-after-free in the DOM: Core & HTML component

Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

--- CME Mitigation Guidance (2026-11-02) --- Disclaimer: The following mitigation solutions are provided as a courtesy, pending the application of an official patch. This content was generated utilizing AI tools in conjunction with data from https://cmetaxonomy.org. Customers are advised to independently evaluate and test these temporary mitigations within their own infrastructure.

The highest-value action is to isolate or restrict DOM processing of untrusted web content in browser and mail clients: upgrade to Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6 (or the corresponding fixed Red Hat builds), which resolves the use-after-free condition within the DOM: Core & HTML component during document object model processing, closing all 2 injection vectors (crafted web page, malicious HTML document). Until patched, this is a concern on Users rendering untrusted web content or HTML messages in Firefox or Thunderbird across any platform, so Restrict users from navigating to untrusted websites and viewing untrusted external HTML content in affected clients. As a compensating measure, Enable ASLR to randomize userspace process memory and impede reliable code execution, Enforce Full RELRO and PIE to harden executable memory sections and hinder memory corruption payloads, and Maintain SELinux in enforcing mode to confine the browser process to least-privilege domains. These controls limit blast radius and contain exploitation, but they do not fix the underlying DOM use-after-free defect — apply the upstream patch to fully remediate.

Highest-impact CME: CME-301 SELinux (Enforcing Mode) (medium)