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{"cveTags": [], "descriptions": [{"lang": "en", "value": "Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 150, Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10."}], "id": "CVE-2026-6746", "lastModified": "2026-04-22T00:16:29.827", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}]}, "published": "2026-04-21T13:16:20.720", "references": [{"source": "security@mozilla.org", "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=2014596"}, {"source": "security@mozilla.org", "url": "https://www.mozilla.org/security/advisories/mfsa2026-30/"}, {"source": "security@mozilla.org", "url": "https://www.mozilla.org/security/advisories/mfsa2026-31/"}, {"source": "security@mozilla.org", "url": "https://www.mozilla.org/security/advisories/mfsa2026-32/"}, {"source": "security@mozilla.org", "url": "https://www.mozilla.org/security/advisories/mfsa2026-33/"}, {"source": "security@mozilla.org", "url": "https://www.mozilla.org/security/advisories/mfsa2026-34/"}], "sourceIdentifier": "security@mozilla.org", "vulnStatus": "Undergoing Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-416"}], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[115.35,115.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[140.10,140.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[150,*]"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Firefox", "source": "cna", "vendor": "Mozilla"}, "product": "firefox", "vendor": "mozilla"}], "analysis": {"en": {"generated_at": "2026-04-21T23:03:28.146808+00:00", "value": {"mitigation_remediation": ["Upgrade to Firefox 150 or later, or to Firefox ESR 115.35 or 140.10 if using an ESR branch.", "Ensure that automatic updates are enabled so that the latest security fixes are applied without manual intervention.", "Monitor Mozilla\u2019s security advisories for future patches and consider applying interim mitigations such as disabling JavaScript or other risky features for untrusted content, while awaiting a permanent fix."], "summary": {"action": "Patch Immediately", "impact": "Use-after-free leading to potential code execution"}, "threat_synthesis": {"affected_systems": "All Mozilla Firefox releases prior to version 150, and the ESR branches below versions 115.35 and 140.10 are vulnerable. Any system running the affected builds is at risk.", "description_and_impact": "This vulnerability is a use\u2011after\u2011free condition in the browser\u2019s DOM core and HTML handling logic. It allows an attacker to exploit a freed memory region that may still be accessed, potentially enabling arbitrary code execution in the context of the browser process. The weakness corresponds to CWE\u2011416 and could compromise confidentiality, integrity, or availability for the affected user if malicious content is processed.", "risk_and_exploitability": "The CVSS score is not provided, but use\u2011after\u2011free bugs in a mainstream browser are generally considered high severity. Since the EPSS score is unavailable and the vulnerability is not listed in CISA KEV, precise exploitation likelihood cannot be quantified. Based on the description, the likely attack vector is through a crafted web page or script that triggers the DOM bug during normal browsing activities."}}}}, "created": "2026-04-21T17:00:11.952872+00:00", "updated": "2026-04-21T23:15:03.115748+00:00", "vendors": ["mozilla", "mozilla$PRODUCT$firefox"], "weaknesses": ["CWE-416"]}