CVE-2026-117927

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 prevent the rendering and parsing of untrusted SVG content in browser and email client sessions: 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 in the SVG component during element handling and rendering, closing all 2 injection vectors (crafted SVG document parsing, malicious webpage rendering SVG content). Until patched, this is a concern on All platforms running affected Firefox or Thunderbird clients processing untrusted web or document content, so avoid opening untrusted SVG files or navigating to untrusted websites rendering SVG content. As a compensating measure, Enable Address Space Layout Randomization to randomize process memory layout and hinder reliable control-flow hijacking. These controls limit blast radius and contain exploitation, but they do not fix the underlying SVG use-after-free defect — apply the upstream patch to fully remediate.

Highest-impact CME: CME-101 ASLR (Address Space Layout Randomization) (medium)