CVE-2026-12321
published 2026-06-16CVE-2026-12321: JIT miscompilation in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 152 and Thunderbird 152.
PriorityP424medium5.4CVSS 3.1
AVNACLPRNUIRSUCLILAN
EPSS
0.16%
5.5th percentile
JIT miscompilation in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 152 and Thunderbird 152.
Affected
4 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| mozilla | firefox | < Firefox 152 | Firefox 152 |
| mozilla | firefox | < 152.0.0 | 152.0.0 |
| mozilla | thunderbird | < Thunderbird 152 | Thunderbird 152 |
| mozilla | thunderbird | < 152.0.0 | 152.0.0 |
CVSS provenance
nvdv3.15.4MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
vendor_redhat5.4MEDIUM
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Red Hat
firefox: thunderbird: JIT miscompilation in the JavaScript: WebAssembly component
vendor_redhat·2026-06-16·CVSS 5.4
CVE-2026-12321 [MEDIUM] CWE-733 firefox: thunderbird: JIT miscompilation in the JavaScript: WebAssembly component
firefox: thunderbird: JIT miscompilation in the JavaScript: WebAssembly component
JIT miscompilation in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 152 and Thunderbird 152.
A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue:
JIT miscompilation in the JavaScript: WebAssembly component
Statement: Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.
Package: firefox (Red Hat Enterprise Linux 10) - Not affected
Package: rhel10/firefox-flatpak (Red Hat Enterprise Linux 10) - Not affected
Package: rhel10/thunderbird-flatpak (Red Hat Enterprise Linux 10) - Not affected
Package: thunderbird (Red Hat Enterprise Linux 10) - Not af
Mozilla
Mozilla Foundation Security Advisory 2026-57: CVE-2026-12321
vendor_mozilla·CVSS 5.4
CVE-2026-12321 [MEDIUM] Mozilla Foundation Security Advisory 2026-57: CVE-2026-12321
Mozilla Foundation Security Advisory 2026-57
CVE: CVE-2026-12321
Product: Firefox
Impact: high
Fixed in: Firefox 152
Mozilla
Mozilla Foundation Security Advisory 2026-60: CVE-2026-12321
vendor_mozilla·CVSS 5.4
CVE-2026-12321 [MEDIUM] Mozilla Foundation Security Advisory 2026-60: CVE-2026-12321
Mozilla Foundation Security Advisory 2026-60
CVE: CVE-2026-12321
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 152
VulDB
Mozilla Firefox up to 151 WebAssembly Remote Code Execution (Nessus ID 321423 / WID-SEC-2026-1959)
vuldb·2026-07-10·CVSS 5.4
CVE-2026-12321 [MEDIUM] Mozilla Firefox up to 151 WebAssembly Remote Code Execution (Nessus ID 321423 / WID-SEC-2026-1959)
A vulnerability described as critical has been identified in Mozilla Firefox up to 151. This issue affects some unknown processing of the component WebAssembly. Executing a manipulation can lead to Remote Code Execution.
This vulnerability is registered as CVE-2026-12321. It is possible to launch the attack remotely. No exploit is available.
Upgrading the affected component is recommended.
GHSA
JIT miscompilation in the JavaScript: WebAssembly component.
ghsa_unreviewed·2026-06-16
CVE-2026-12321 [MEDIUM] CWE-670 JIT miscompilation in the JavaScript: WebAssembly component.
JIT miscompilation in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 152.
No detection rules found.
No public exploits indexed.
2026-06-16
Published