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CVE-2026-16392

Mozilla Firefox, Thunderbird

JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 153 and Thunderbird 153.

CVSS
9.1
EPSS
0.39%
31.3% percentile
CISA KEV
Not listed
Published
2026.07.21
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.39%
Technical severityCVSS 9.1

Vulnerability overview

JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 153 and Thunderbird 153.

Affected product and versions

Product
Mozilla Firefox, Thunderbird
Affected versions
See the vendor advisory and NVD configuration data
Fixed versions
No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Mozilla Firefox, Thunderbird and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
CWE
CWE-670, CWE-843