CVE-2026-5735
Full vulnerability record from the local CVENow database.
Description
Memory safety bugs present in Firefox 149.0.1 and Thunderbird 149.0.1. 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 was fixed in Firefox 149.0.2 and Thunderbird 149.0.2.
Severity
CRITICAL
CVSS score
9.8
(v3.1)
Vulnerability status
Modified
Source identifier
Published
2026-04-07 13:16:47.763000
Last modified
2026-10-23 23:10:00.157000
View original CVE JSON
{
"id": "CVE-2026-5735",
"sourceIdentifier": "[email protected]",
"published": "2026-04-07T13:16:47.763",
"lastModified": "2026-10-23T23:10:00.157",
"vulnStatus": "Modified",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "Memory safety bugs present in Firefox 149.0.1 and Thunderbird 149.0.1. 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 was fixed in Firefox 149.0.2 and Thunderbird 149.0.2."
},
{
"lang": "es",
"value": "Errores de seguridad de memoria presentes en Firefox 149.0.1 y Thunderbird 149.0.1. Algunos de estos errores mostraron evidencia de corrupción de memoria y presumimos que con suficiente esfuerzo algunos de estos podrían haber sido explotados para ejecutar código arbitrario. Esta vulnerabilidad afecta a Firefox anterior a 149.0.2 y Thunderbird anterior a 149.0.2."
}
],
"affected": [
{
"source": "[email protected]",
"affectedData": [
{
"vendor": "Mozilla",
"product": "Firefox",
"versions": [
{
"version": "149.0.2",
"lessThanOrEqual": "*",
"versionType": "rpm",
"status": "unaffected"
}
]
},
{
"vendor": "Mozilla",
"product": "Thunderbird",
"versions": [
{
"version": "149.0.2",
"lessThanOrEqual": "*",
"versionType": "rpm",
"status": "unaffected"
}
]
}
]
},
{
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"affectedData": [
{
"vendor": "Red Hat",
"product": "Red Hat Enterprise Linux 10",
"defaultStatus": "unaffected",
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"packageName": "firefox",
"cpes": [
"cpe:/o:redhat:enterprise_linux:10"
]
},
{
"vendor": "Red Hat",
"product": "Red Hat Enterprise Linux 10",
"defaultStatus": "unaffected",
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"packageName": "rhel10/firefox-flatpak",
"cpes": [
"cpe:/o:redhat:enterprise_linux:10"
]
},
{
"vendor": "Red Hat",
"product": "Red Hat Enterprise Linux 6",
"defaultStatus": "unaffected",
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"packageName": "firefox",
"cpes": [
"cpe:/o:redhat:enterprise_linux:6"
]
},
{
"vendor": "Red Hat",
"product": "Red Hat Enterprise Linux 7",
"defaultStatus": "unaffected",
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"packageName": "firefox",
"cpes": [
"cpe:/o:redhat:enterprise_linux:7"
]
},
{
"vendor": "Red Hat",
"product": "Red Hat Enterprise Linux 8",
"defaultStatus": "unaffected",
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"packageName": "firefox",
"cpes": [
"cpe:/o:redhat:enterprise_linux:8"
]
},
{
"vendor": "Red Hat",
"product": "Red Hat Enterprise Linux 9",
"defaultStatus": "unaffected",
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"packageName": "firefox",
"cpes": [
"cpe:/o:redhat:enterprise_linux:9"
]
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "[email protected]",
"type": "Primary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"baseScore": 9.8,
"baseSeverity": "CRITICAL",
"attackVector": "NETWORK",
"attackComplexity": "LOW",
"privilegesRequired": "NONE",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"availabilityImpact": "HIGH"
},
"exploitabilityScore": 3.9,
"impactScore": 5.9
},
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
"baseScore": 8.1,
"baseSeverity": "HIGH",
"attackVector": "NETWORK",
"attackComplexity": "HIGH",
"privilegesRequired": "NONE",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"availabilityImpact": "HIGH"
},
"exploitabilityScore": 2.2,
"impactScore": 5.9
},
{
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"type": "Secondary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H",
"baseScore": 7.5,
"baseSeverity": "HIGH",
"attackVector": "NETWORK",
"attackComplexity": "HIGH",
"privilegesRequired": "NONE",
"userInteraction": "REQUIRED",
"scope": "UNCHANGED",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"availabilityImpact": "HIGH"
},
"exploitabilityScore": 1.6,
"impactScore": 5.9
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"timestamp": "2026-04-08T03:55:32.503768Z",
"id": "CVE-2026-5735",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "total"
}
],
"role": "CISA Coordinator",
"version": "2.0.3"
}
}
]
},
"weaknesses": [
{
"source": "[email protected]",
"type": "Primary",
"description": [
{
"lang": "en",
"value": "CWE-787"
}
]
},
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary",
"description": [
{
"lang": "en",
"value": "CWE-125"
},
{
"lang": "en",
"value": "CWE-787"
}
]
},
{
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"type": "Secondary",
"description": [
{
"lang": "en",
"value": "CWE-787"
}
]
}
],
"configurations": [
{
"nodes": [
{
"operator": "OR",
"negate": false,
"cpeMatch": [
{
"vulnerable": true,
"criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*",
"versionEndExcluding": "149.0.2",
"matchCriteriaId": "CF910B3C-C241-48B5-9066-260750E8E7ED"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*",
"versionEndExcluding": "149.0.2",
"matchCriteriaId": "5FB6BDEF-D9FC-4C5C-9098-03DCA98223D3"
}
]
}
]
}
],
"references": [
{
"url": "https://bugzilla.mozilla.org/buglist.cgi?bug_id=2025475%2C2025477",
"source": "[email protected]",
"tags": [
"Broken Link",
"Issue Tracking"
]
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2026-25/",
"source": "[email protected]",
"tags": [
"Vendor Advisory"
]
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2026-28/",
"source": "[email protected]"
},
{
"url": "https://access.redhat.com/security/cve/CVE-2026-5735",
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"
},
{
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2455904",
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"
},
{
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-5735.json",
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"
}
]
}