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PatchSiren cyber security CVE debrief

CVE-2026-12307 Mozilla CVE debrief

CVE-2026-12307 is a memory safety bug that was fixed in Firefox 152 and Firefox ESR 140.12. The bug was reported and fixed, with no evidence of exploitation or ransomware campaign use.

Vendor
Mozilla
Product
Firefox
CVSS
MEDIUM 5.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-16
Original CVE updated
2026-06-18
Advisory published
2026-06-16
Advisory updated
2026-06-18

Who should care

Users of Firefox 152 and Firefox ESR 140.12 should ensure they have updated to the latest versions to mitigate this vulnerability.

Technical summary

A memory safety bug was fixed in Firefox 152. This vulnerability was fixed in Firefox 152 and Firefox ESR 140.12.

Defensive priority

medium

Recommended defensive actions

  • Update to Firefox 152 or Firefox ESR 140.12 to mitigate this vulnerability.

Evidence notes

The CVE was published and modified on 2026-06-16T13:16:30.933Z. The vendor is likely Mozilla, based on the evidence.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-12307 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-12307

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

  • CVE-2026-12307 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-12307

    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.