What’s Vulnerable › Vulnerabilities

CVE-2026-2804: Use-after-free in the JavaScript: WebAssembly component

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-02-24 · updated 2026-06-17
• Weakness: CWE-416

Description

Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 148 and Thunderbird 148.

Affected products

• Mozilla Firefox: before 148.0 — fixed in 148.0
• Mozilla Thunderbird: before 148.0 — fixed in 148.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 148.0; Mozilla Thunderbird 148.0. Check the vendor advisory for mitigations.

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=2013584
• https://www.mozilla.org/security/advisories/mfsa2026-13/
• https://www.mozilla.org/security/advisories/mfsa2026-16/

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