{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-4729", "assignerOrgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe", "state": "PUBLISHED", "assignerShortName": "mozilla", "dateReserved": "2026-03-23T23:22:57.190Z", "datePublished": "2026-03-24T12:30:43.835Z", "dateUpdated": "2026-03-25T13:08:59.287Z"}, "containers": {"cna": {"affected": [{"product": "Firefox", "vendor": "Mozilla", "versions": [{"lessThan": "149", "status": "affected", "version": "unspecified", "versionType": "custom"}]}, {"product": "Thunderbird", "vendor": "Mozilla", "versions": [{"lessThan": "149", "status": "affected", "version": "unspecified", "versionType": "custom"}]}], "descriptions": [{"lang": "en", "value": "Memory safety bugs present in Firefox 148 and Thunderbird 148. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 149 and Thunderbird < 149.", "supportingMedia": [{"type": "text/html", "base64": false, "value": "Memory safety bugs present in Firefox 148 and Thunderbird 148. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 149 and Thunderbird < 149."}]}], "title": "Memory safety bugs fixed in Firefox 149 and Thunderbird 149", "references": [{"url": "https://bugzilla.mozilla.org/buglist.cgi?bug_id=1944033%2C1997282%2C2009213%2C2011412%2C2021925%2C2022034", "name": "Memory safety bugs fixed in Firefox 149 and Thunderbird 149"}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-20/"}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-23/"}], "credits": [{"lang": "en", "value": "Christian Holler, Fatih Kilic, Tom Schuster and the Mozilla Fuzzing Team"}], "providerMetadata": {"orgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe", "shortName": "mozilla", "dateUpdated": "2026-03-24T20:27:55.597Z"}}, "adp": [{"problemTypes": [{"descriptions": [{"type": "CWE", "cweId": "CWE-120", "lang": "en", "description": "CWE-120 Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')"}]}], "metrics": [{"cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 9.8, "attackVector": "NETWORK", "baseSeverity": "CRITICAL", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}}, {"other": {"type": "ssvc", "content": {"timestamp": "2026-03-25T03:56:12.370422Z", "id": "CVE-2026-4729", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "total"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-03-25T13:08:59.287Z"}}]}}

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{"configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*", "matchCriteriaId": "02F2B82F-E997-4D5F-BBB0-237E4962555B", "versionEndExcluding": "149.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*", "matchCriteriaId": "40FE4697-89F1-46F6-8E28-41883647583B", "versionEndExcluding": "149.0", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Memory safety bugs present in Firefox 148 and Thunderbird 148. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 149 and Thunderbird < 149."}, {"lang": "es", "value": "Errores de seguridad de memoria presentes en Firefox 148 y Thunderbird 148. Algunos de estos errores mostraron evidencia de corrupci\u00f3n de memoria y presumimos que con suficiente esfuerzo algunos de estos podr\u00edan haber sido explotados para ejecutar c\u00f3digo arbitrario. Esta vulnerabilidad afecta a Firefox &lt; 149 y Thunderbird &lt; 149."}], "id": "CVE-2026-4729", "lastModified": "2026-03-25T20:54:55.353", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}]}, "published": "2026-03-24T13:16:08.830", "references": [{"source": "security@mozilla.org", "tags": ["Broken Link"], "url": "https://bugzilla.mozilla.org/buglist.cgi?bug_id=1944033%2C1997282%2C2009213%2C2011412%2C2021925%2C2022034"}, {"source": "security@mozilla.org", "tags": ["Vendor Advisory"], "url": "https://www.mozilla.org/security/advisories/mfsa2026-20/"}, {"source": "security@mozilla.org", "tags": ["Vendor Advisory"], "url": "https://www.mozilla.org/security/advisories/mfsa2026-23/"}], "sourceIdentifier": "security@mozilla.org", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-120"}], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}]}

{"bugzilla": {"description": "firefox: Memory safety bugs fixed in Firefox 149 and Thunderbird 149", "id": "2450745", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2450745"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.5", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-825", "details": ["A flaw was found in Firefox. The Mozilla Foundation's Security Advisory describes the following issue:\nMemory safety bugs present in Firefox 148 and Thunderbird 148. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code."], "name": "CVE-2026-4729", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "package_name": "rhel10/firefox-flatpak", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-03-24T12:30:43Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-4729\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-4729\nhttps://www.mozilla.org/security/advisories/mfsa2026-20/#CVE-2026-4729"], "statement": "Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.", "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[0,149)"}}], "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": "2026-03-25T23:49:47.901110+00:00", "value": {"mitigation_remediation": ["Upgrade Mozilla Firefox to version 149 or newer if not already installed.", "Upgrade Mozilla Thunderbird to version 149 or newer if not already installed.", "If an upgrade is not immediately possible, monitor Mozilla security advisories and apply any released patches as soon as they become available."], "summary": {"action": "Immediate Patch", "impact": "Remote Code Execution"}, "threat_synthesis": {"affected_systems": "The affected products are Mozilla Firefox and Mozilla Thunderbird, specifically any installation with a version older than 149. Versions 148 and earlier are impacted; all releases 149 and later have the fixes applied.", "description_and_impact": "Memory safety bugs were reported in Firefox and Thunderbird releases prior to version 149. The bugs caused memory corruption that, with sufficient effort, could be used to execute arbitrary code. The primary impact is that an attacker could gain full control of the affected system by exploiting these bugs. The weakness falls under corruption of input buffers and related memory errors.", "risk_and_exploitability": "The CVSS score of 9.8 indicates a critical severity. The EPSS score is below 1%, suggesting that current exploitation attempts are unlikely, and the vulnerability is not listed in the CISA KEV catalog. Nevertheless, because the bugs allow arbitrary code execution, they pose a high risk if the systems remain unpatched. The attack vector is inferred to be possible through crafted web content or email attachments, as common vector mechanisms for memory corruption in browsers and mail clients. An attacker does not need special credentials; local access to the user\u2019s session would be sufficient to load malicious content."}}}}, "created": "2026-03-25T11:47:43.193855+00:00", "updated": "2026-03-26T12:19:45.471635+00:00", "vendors": ["mozilla", "mozilla$PRODUCT$firefox"]}