CVE-2026-117935

A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue: Use-after-free in the DOM: Bindings (WebIDL) 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 (2026-11-03) --- 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 correct object lifecycle and memory management within the DOM WebIDL bindings component to prevent use-after-free conditions: 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 memory safety flaw in the DOM WebIDL bindings component, closing crafted web page invoking DOM WebIDL bindings. Until patched, this is a concern on systems running affected browser installations where users access untrusted web content, so restrict user navigation to untrusted websites and prevent opening untrusted web content in affected browser sessions. As a compensating measure, enable Address Space Layout Randomization to randomize browser userspace memory layout and impede memory address prediction, enforce Full RELRO and PIE to ensure binary position independence and write-protect the Global Offset Table against overwrites, and run SELinux in enforcing mode to apply mandatory access controls and restrict browser process access to system resources. These controls limit blast radius and contain exploitation, but they do not fix the underlying use-after-free defect — apply the upstream patch to fully remediate.

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