{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-6759", "assignerOrgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe", "state": "PUBLISHED", "assignerShortName": "mozilla", "dateReserved": "2026-04-21T12:40:54.035Z", "datePublished": "2026-04-21T12:40:54.329Z", "dateUpdated": "2026-04-21T23:34:51.428Z"}, "containers": {"cna": {"affected": [{"product": "Firefox", "vendor": "Mozilla", "versions": [{"status": "unaffected", "version": "140.10", "lessThanOrEqual": "140.*", "versionType": "rpm"}, {"status": "unaffected", "version": "150", "lessThanOrEqual": "*", "versionType": "rpm"}]}, {"product": "Thunderbird", "vendor": "Mozilla", "versions": [{"status": "unaffected", "version": "140.10", "lessThanOrEqual": "140.*", "versionType": "rpm"}, {"status": "unaffected", "version": "150", "lessThanOrEqual": "*", "versionType": "rpm"}]}], "descriptions": [{"lang": "en", "value": "Use-after-free in the Widget: Cocoa component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.", "supportingMedia": [{"type": "text/html", "base64": false, "value": "Use-after-free in the Widget: Cocoa component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10."}]}], "title": "Use-after-free in the Widget: Cocoa component", "references": [{"url": "https://bugzilla.mozilla.org/show_bug.cgi?id=2016164"}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-30/"}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-32/"}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-33/"}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-34/"}], "credits": [{"lang": "en", "value": "Steven Michaud"}], "providerMetadata": {"orgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe", "shortName": "mozilla", "dateUpdated": "2026-04-21T23:34:51.428Z"}}, "adp": [{"problemTypes": [{"descriptions": [{"type": "CWE", "cweId": "CWE-416", "lang": "en", "description": "CWE-416 Use After Free"}]}], "metrics": [{"cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}}, {"other": {"type": "ssvc", "content": {"timestamp": "2026-04-21T17:48:09.982914Z", "id": "CVE-2026-6759", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-04-21T17:48:52.709Z"}}]}}

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{"cveTags": [], "descriptions": [{"lang": "en", "value": "Use-after-free in the Widget: Cocoa component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10."}], "id": "CVE-2026-6759", "lastModified": "2026-04-22T00:16:31.870", "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": "2026-04-21T13:16:21.857", "references": [{"source": "security@mozilla.org", "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=2016164"}, {"source": "security@mozilla.org", "url": "https://www.mozilla.org/security/advisories/mfsa2026-30/"}, {"source": "security@mozilla.org", "url": "https://www.mozilla.org/security/advisories/mfsa2026-32/"}, {"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": "[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": "2026-04-22T07:33:34.871321+00:00", "value": {"mitigation_remediation": ["Upgrade to Firefox\u00a0150 or newer, or to Firefox ESR\u00a0140.10 or newer, to apply the fix for this use\u2011after\u2011free flaw.", "Upgrade to Thunderbird\u00a0150 or newer, or to Thunderbird ESR\u00a0140.10 or newer, to apply the fix for this use\u2011after\u2011free flaw.", "If an upgrade cannot be performed immediately, consider disabling the Widget: Cocoa component or other widget APIs that are not required for your use case to eliminate the vulnerability exposure.", "Keep both Firefox and Thunderbird updated regularly and monitor Mozilla\u2019s security advisories for any additional patches or guidance related to the Widget component."], "summary": {"action": "Immediate Patch", "impact": "Arbitrary code execution"}, "threat_synthesis": {"affected_systems": "Mozilla Firefox versions older than 150 and Firefox ESR 140.10, and Mozilla Thunderbird versions older than 150 and Thunderbird ESR 140.10, are affected.", "description_and_impact": "The vulnerability is a use\u2011after\u2011free flaw in Mozilla\u2019s Widget: Cocoa component that exists in both Firefox and Thunderbird. The component can free an object while it is still in use, which can corrupt memory and potentially cause the application to crash or execute attacker\u2011controlled code if the freed memory is later reused.", "risk_and_exploitability": "The CVSS score of 7.5 indicates high severity, while the EPSS score is not available, so the exploitation probability is uncertain. The vulnerability is not listed in CISA\u2019s KEV catalog. The likely attack vector is within the application process, possibly via a malicious webpage, email message, or user interaction that triggers the Widget: Cocoa code path (this inference is based on typical use\u2011after\u2011free exploitation scenarios)."}}}}, "created": "2026-04-21T17:45:16.246338+00:00", "updated": "2026-04-22T07:45:11.734769+00:00", "vendors": ["mozilla", "mozilla$PRODUCT$firefox"]}