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CVE-2026-12294 Mozilla CVE debrief

CVE-2026-12294 is a vulnerability in the DOM: Workers component that allows for sandbox escape. The vulnerability was fixed in Firefox 152, Firefox ESR 140.12, and Firefox ESR 115.37. The CVE was published on [cvePublishedAt](https://www.cve.org/CVERecord?id=CVE-2026-12294) and last modified on [cveModifiedAt](https://www.cve.org/CVERecord?id=CVE-2026-12294).

Vendor
Mozilla
Product
Firefox
CVSS
CRITICAL 9.6
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-16
Original CVE updated
2026-07-15
Advisory published
2026-06-16
Advisory updated
2026-07-15

Who should care

Users of Firefox, Firefox ESR, and other products that use the DOM: Workers component should apply the fixes provided by Mozilla.

Technical summary

The vulnerability is a sandbox escape in the DOM: Workers component. This could potentially allow an attacker to execute arbitrary code outside of the sandbox.

Defensive priority

high

Recommended defensive actions

  • Apply the fixes provided by Mozilla: update to Firefox 152, Firefox ESR 140.12, or Firefox ESR 115.37.

Evidence notes

The CVE was published by [cve-org](https://www.cve.org/CVERecord?id=CVE-2026-12294) and detailed by [nvd](https://nvd.nist.gov/vuln/detail/CVE-2026-12294).

Sources and references

Verified primary and authoritative sources

  • CVE-2026-12294 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-12294

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

  • CVE-2026-12294 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-12294

    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.