CVE-2026-117913

A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue: Use-after-free in the SVG 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 isolate or restrict processing of untrusted SVG content in the Firefox rendering engine: upgrade to Firefox 159 and Firefox ESR 153.6 (or the corresponding fixed Red Hat builds), which resolves the use-after-free condition triggered during SVG element rendering and processing, closing crafted SVG documents. Until patched, this is a concern on all platforms where users open untrusted content or navigate to malicious web pages in affected Firefox installations, so restrict user interaction with untrusted websites and avoid opening untrusted SVG files in the browser. As a compensating measure, ensure Address Space Layout Randomization is enforced on Firefox processes to hinder predicting memory locations needed for reliable code execution. 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-101 ASLR (Address Space Layout Randomization) (medium)