CVE-2026-16363CWE-682CWE-843

CVE-2026-16363

Critical · published July 21, 2026

CVSS v3.1
9.8
EPSS
0%
Percentile
36.9
In the wild
Unconfirmed
What it is

JIT miscompilation in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.

The record
Technical detail
CVSS v3.1
9.8 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00436 · 36.9th percentile
Weaknesses
CWE-682 · Incorrect Calculation; CWE-843 · Access of Resource Using Incompatible Type ('Type Confusion')
Published
2026-07-21T17:17Z
Affected products (4)
ProductVersionsFixed in
mozilla/firefox< 140.13.0140.13.0
mozilla/firefox< 153.0.0153.0.0
mozilla/thunderbird< 140.13.0140.13.0
mozilla/thunderbird≥ 141.0, < 153.0153.0
References (5)
https://bugzilla.mozilla.org/show_bug.cgi?id=2047689 · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-68/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-70/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-71/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-72/ · [email protected]
EPSS history
Timeline
  • 21 JUL 12:37Z
    JIT miscompilation in the JavaScript: WebAssembly component
    cvelistv5