Junglewise Threat Intelligence

CVE-2026-8390: Mozilla Firefox use-after-free in WebAssembly component

CVE-2026-8390 · Severity: high · CVSS 7.3 · Published 2026-05-12

Technologies: Mozilla Firefox. Vendors: Mozilla.

Executive brief

A memory management vulnerability was identified in the WebAssembly component of the Mozilla Firefox web browser. An attacker could potentially exploit this flaw to cause a browser crash or execute unauthorized code when a user visits a malicious website. This could lead to the theft of sensitive information or a compromise of the user's system.

Technical details

A use-after-free (UAF) vulnerability exists in the JavaScript: WebAssembly component of Mozilla Firefox. The flaw is triggered when the engine attempts to access memory that has already been deallocated, often due to improper pointer management (CWE-416/CWE-825). An attacker can exploit this by enticing a user to process specially crafted WebAssembly content, potentially leading to a heap-based buffer overflow or arbitrary code execution within the context of the browser process. The vulnerability is resolved in Firefox version 150.0.3.

Affected products

  • Mozilla Firefox before 150.0.3

Timeline

  • 2026-05-12: disclosed
  • 2026-05-12: advisory
  • 2026-05-12: patched: Fixed in Firefox 150.0.3

References

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