CVE-2026-4701 - Vulnerability Analysis

Overview

Firefox < 149 and Firefox ESR < 140.9 contain a use-after-free vulnerability in the JavaScript Engine component, letting attackers cause memory corruption or remote code execution, exploit requires crafted web content.

Severity & Score

Impact

Attackers can cause memory corruption or execute arbitrary code remotely via crafted web content.

Mitigation

Update to Firefox 149, Firefox ESR 140.9 or later.

References

• https://www.mozilla.org/security/advisories/mfsa2026-22/
• https://www.mozilla.org/security/advisories/mfsa2026-23/
• https://www.mozilla.org/security/advisories/mfsa2026-24/
• https://bugzilla.mozilla.org/show_bug.cgi?id=2009303
• https://www.mozilla.org/security/advisories/mfsa2026-20/

Social Media Activity(1 post)

TheHackerWire

@thehackerwire

Mar 24, 2026

🔴 CVE-2026-4701 - Critical (9.8) Use-after-free in the JavaScript Engine component. This vulnerability affects Firefox < 149, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9. 🔗 https://www.thehackerwire.com/vulnerability/CVE-2026-4701/ #CVE #vulnerability #infosec #cybersecurity #security #Tenda #patchstack

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