CVE-2026-12321: JIT miscompilation in the JavaScript: WebAssembly component
JIT miscompilation in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 152 and Thunderbird 152.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 152 - Upgrade
Upgrade
Firefoxto a version that resolves this vulnerability.Fixed in 152 - Upgrade
Upgrade
Thunderbirdto a version that resolves this vulnerability.Fixed in 152
Event History
Peer vulnerabilities
Found alongside the following vulnerabilities.
- CVE-2026-12289
- CVE-2026-12290
- CVE-2026-12291
- CVE-2026-12292
- CVE-2026-12293
- CVE-2026-12294
- CVE-2026-12295
- CVE-2026-12296
- CVE-2026-12297
- CVE-2026-12298
- CVE-2026-12299
- CVE-2026-12300
- CVE-2026-12301
- CVE-2026-12302
- CVE-2026-12303
- CVE-2026-12304
- CVE-2026-12305
- CVE-2026-12306
- CVE-2026-12307
- CVE-2026-12308
- CVE-2026-12309
- CVE-2026-12310
- CVE-2026-12311
- CVE-2026-12312
- CVE-2026-12313
- CVE-2026-12314
- CVE-2026-12315
- CVE-2026-12316
- CVE-2026-12317
- CVE-2026-12318
- CVE-2026-12319
- CVE-2026-12320
- CVE-2026-12321
- CVE-2026-12322
- CVE-2026-12323
- CVE-2026-12324
- CVE-2026-12325
- CVE-2026-12326
- CVE-2026-12327
- CVE-2026-12328
Frequently Asked Questions
What is the severity of CVE-2026-12321?
The severity of CVE-2026-12321 is medium, with a CVSS score of 5.4.
How do I fix CVE-2026-12321?
To fix CVE-2026-12321, update to Firefox version 152 or Thunderbird version 152 or later.
What software is affected by CVE-2026-12321?
CVE-2026-12321 affects Mozilla Firefox and Mozilla Thunderbird.
When was CVE-2026-12321 published?
CVE-2026-12321 was published on June 16, 2026.
What is the nature of the vulnerability in CVE-2026-12321?
CVE-2026-12321 involves JIT miscompilation in the JavaScript: WebAssembly component.