CVE-2026-117875

A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue: Use-after-free in the Layout: Scrolling and Overflow 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 eliminate use-after-free memory corruption during layout processing in the Scrolling and Overflow component: upgrade to Firefox 159, Firefox ESR 153.6, Thunderbird 159 (or the corresponding fixed Red Hat builds), which resolves the use-after-free memory corruption condition triggered during layout processing in the Scrolling and Overflow component, closing all 2 injection vectors (crafted web page navigation, crafted HTML content rendered in a browser-like context). Until patched, this is a concern on Systems running Firefox or Thunderbird that render untrusted web pages or HTML content across all platforms, so Restrict users from navigating to untrusted web pages and avoid rendering untrusted HTML content in browser or browser-like contexts. As a compensating measure, Ensure Address Space Layout Randomization is enforced to randomize browser process memory and impede arbitrary 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)