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CVE-2026-12303 Mozilla CVE debrief

CVE-2026-12303 is an information disclosure vulnerability due to incorrect boundary conditions in the Graphics: WebGPU component. The issue was fixed in Firefox 152. According to [nvd](https://nvd.nist.gov/vuln/detail/CVE-2026-12303), this CVE was published and modified on 2026-06-16T13:16:30.557Z. For more information, refer to the [CVE record](https://www.cve.org/CVERecord?id=CVE-2026-12303) and [Mozilla security advisories](https://www.mozilla.org/security/advisories/mfsa2026-57/).

Vendor
Mozilla
Product
Firefox
CVSS
MEDIUM 4.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-16
Original CVE updated
2026-06-16
Advisory published
2026-06-16
Advisory updated
2026-06-16

Who should care

Users of Firefox browser, particularly those using versions prior to Firefox 152, should be aware of this vulnerability and update their browsers to mitigate potential information disclosure risks.

Technical summary

The vulnerability is caused by incorrect boundary conditions in the Graphics: WebGPU component of Firefox. This could lead to information disclosure. The issue has been addressed in Firefox 152.

Defensive priority

Medium

Recommended defensive actions

  • Update Firefox to version 152 or later.
  • Refer to [Mozilla security advisories](https://www.mozilla.org/security/advisories/mfsa2026-57/) for more information.

Evidence notes

The CVE was published and modified on 2026-06-16T13:16:30.557Z. The vendor is identified as Unknown Vendor with low confidence, and evidence suggests Mozilla might be the affected vendor.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-12303 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-12303

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

  • CVE-2026-12303 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-12303

    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.