CVE-2026-117902

A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue: Use-after-free in the Layout: Text and Fonts 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 prevent execution of memory-unsafe operations during layout, text, and font rendering in browser engines: upgrade to Firefox 159 and Firefox ESR 153.6 (or the corresponding fixed Red Hat builds), which corrects memory lifetime management to prevent use-after-free conditions in the Layout: Text and Fonts component, closing all 2 injection vectors (crafted web page rendering text or fonts, crafted font or layout processing in a browser-like context). Until patched, this is a concern on users navigating to untrusted websites or viewing untrusted web content across all platforms, so restrict user navigation to untrusted websites and viewing of untrusted web content in affected browser sessions. As a compensating measure, enforce Address Space Layout Randomization to impede predictable control-flow redirection or ROP payload execution resulting from memory corruption. 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)