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CVE-2026-12296 Mozilla CVE debrief

CVE-2026-12296 is a sandbox escape vulnerability in the Security: Process Sandboxing component. The vulnerability was fixed in Firefox 152 and Firefox ESR 140.12. The CVE was published and modified on June 16, 2026.

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 and Firefox ESR should update to Firefox 152 and Firefox ESR 140.12 to mitigate this vulnerability.

Technical summary

A sandbox escape vulnerability exists in the Security: Process Sandboxing component. This vulnerability could potentially allow an attacker to escape the sandbox and execute arbitrary code.

Defensive priority

High

Recommended defensive actions

  • Update to Firefox 152 or Firefox ESR 140.12

Evidence notes

The CVE record and NVD detail can be found at [cve-org] and [nvd], respectively. Additional information can be found in the Mozilla security advisories [ref-5] and [ref-6].

Sources and references

Verified primary and authoritative sources

  • CVE-2026-12296 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-12296

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

  • CVE-2026-12296 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-12296

    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.