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CVE-2026-16392 Mozilla CVE debrief

CVE-2026-16392 is a JIT miscompilation vulnerability in the JavaScript Engine's JIT component. The vulnerability was fixed in Firefox 153 and Thunderbird 153. This type of vulnerability could potentially allow for arbitrary code execution if exploited. Users of Firefox and Thunderbird should update to versions 153 to address this vulnerability. The vulnerability's impact is considered high, and users should review the CVE record and NVD detail for more information.

Vendor
Mozilla
Product
Firefox
CVSS
CRITICAL 9.1
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-21
Original CVE updated
2026-08-06
Advisory published
2026-07-21
Advisory updated
2026-08-06

Who should care

Users of Firefox and Thunderbird should update to versions 153 to address this vulnerability. This includes individuals and organizations using these products for browsing and email. The vulnerability's impact is considered high, and users should review the CVE record and NVD detail for more information. Security teams should verify their deployments and plan updates or mitigations through normal change control.

Technical summary

The JIT miscompilation vulnerability in the JavaScript Engine's JIT component could potentially allow for arbitrary code execution if exploited. The vulnerability was addressed in Firefox 153 and Thunderbird 153. This type of vulnerability typically involves the engine's just-in-time compilation process, which can be manipulated under certain conditions. Users should ensure their browsers are updated to prevent potential exploitation.

Defensive priority

High

Recommended defensive actions

  • Update Firefox to version 153 or later
  • Update Thunderbird to version 153 or later
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
  • Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance

Evidence notes

The CVE record and NVD detail provide information on the vulnerability. Additional information can be found in the Mozilla security advisories. Users should verify their deployments and review official advisories for affected scope and severity. Defenders should check for exposure and plan updates or mitigations through normal change control.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-16392 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-16392

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-16392 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-16392

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.