Use-After-Free Vulnerability in Mozilla Firefox JavaScript Engine
CVE-2026-2764

9.8CRITICAL

Key Information:

Vendor

Mozilla
Status
Firefox
Thunderbird
Vendor
CVE Published:
24 February 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-2764?

This vulnerability is identified as an issue in the JavaScript Engine of Mozilla Firefox, specifically within the JIT (Just-In-Time) compilation process. It allows attackers to exploit a use-after-free condition, potentially enabling arbitrary code execution. The flaw impacts various versions of Firefox and its Extended Support Release (ESR), making it crucial for users to upgrade to the latest versions to mitigate any associated risks.

Affected Version(s)

Firefox 115.33

Firefox 140.8

Firefox 148

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-2764-but-with-wasm
Created by SneakyNachos

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2012608
https://www.mozilla.org/security/advisories/mfsa2026-13/
https://www.mozilla.org/security/advisories/mfsa2026-14/

CVSS V3.1

Score:
9.8
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Information to follow
.