What’s Vulnerable › Vulnerabilities

CVE-2026-92040: Use-after-free in the JavaScript: WebAssembly component

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-15 · updated 2026-10-05
• Weakness: CWE-416

Description

Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 156 and Thunderbird 156.

Affected products

• Mozilla Firefox: before 156.0.0 — fixed in 156.0.0
• Mozilla Thunderbird: before 156.0 — fixed in 156.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 156.0.0; Mozilla Thunderbird 156.0. Check the vendor advisory for mitigations.

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=2024248
• https://www.mozilla.org/security/advisories/mfsa2026-90/
• https://www.mozilla.org/security/advisories/mfsa2026-94/

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