CVE-2026-8948

Same-origin policy bypass in the DOM: Networking component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

CVSS v3 9.1 CRITICAL

9.1^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://bugzilla.mozilla.org/show_bug.cgi?id=2038803	Permissions Required
https://www.mozilla.org/security/advisories/mfsa2026-46/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-50/	Vendor Advisory
https://access.redhat.com/security/cve/CVE-2026-8948
https://bugzilla.redhat.com/show_bug.cgi?id=2479850
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-8948.json

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:mozilla:firefox:::::-:::*
	cpe:2.3:a:mozilla:thunderbird::::::::

History

No history.

Information

Published : 2026-05-19 14:16

Updated : 2026-07-15 01:17

NVD link : CVE-2026-8948

Mitre link : CVE-2026-8948

CVE.ORG link : CVE-2026-8948

JSON object : View

Products Affected

mozilla

thunderbird
firefox

CWE

CWE-942

Permissive Cross-domain Security Policy with Untrusted Domains

CWE-79

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

{"id": "CVE-2026-8948", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-8948", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "total"}], "version": "2.0.3", "timestamp": "2026-05-19T16:40:44.630280Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 9.1, "attackVector": "NETWORK", "baseSeverity": "CRITICAL", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 5.2, "exploitabilityScore": 3.9}, {"type": "Secondary", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "REQUIRED", "attackComplexity": "HIGH", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 1.6}]}, "affected": [{"source": "security@mozilla.org", "affectedData": [{"vendor": "Mozilla", "product": "Firefox", "versions": [{"status": "unaffected", "version": "151", "versionType": "rpm", "lessThanOrEqual": "*"}]}, {"vendor": "Mozilla", "product": "Thunderbird", "versions": [{"status": "unaffected", "version": "151", "versionType": "rpm", "lessThanOrEqual": "*"}]}]}, {"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "affectedData": [{"cpes": ["cpe:/o:redhat:enterprise_linux:10"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 10", "packageName": "firefox", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:10"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 10", "packageName": "rhel10/firefox-flatpak", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:10"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 10", "packageName": "rhel10/thunderbird-flatpak", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:10"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 10", "packageName": "thunderbird", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:6"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 6", "packageName": "firefox", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:6"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 6", "packageName": "thunderbird", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:7"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 7", "packageName": "firefox", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:7"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 7", "packageName": "thunderbird", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:8"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 8", "packageName": "firefox", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:8"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 8", "packageName": "thunderbird", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:9"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 9", "packageName": "firefox", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:9"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 9", "packageName": "thunderbird", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}]}], "published": "2026-05-19T14:16:51.027", "references": [{"url": "https://bugzilla.mozilla.org/show_bug.cgi?id=2038803", "tags": ["Permissions Required"], "source": "security@mozilla.org"}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-46/", "tags": ["Vendor Advisory"], "source": "security@mozilla.org"}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-50/", "tags": ["Vendor Advisory"], "source": "security@mozilla.org"}, {"url": "https://access.redhat.com/security/cve/CVE-2026-8948", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2479850", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}, {"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-8948.json", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}], "vulnStatus": "Modified", "weaknesses": [{"type": "Secondary", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "description": [{"lang": "en", "value": "CWE-942"}]}, {"type": "Secondary", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "description": [{"lang": "en", "value": "CWE-79"}]}], "descriptions": [{"lang": "en", "value": "Same-origin policy bypass in the DOM: Networking component. This vulnerability was fixed in Firefox 151 and Thunderbird 151."}], "lastModified": "2026-07-15T01:17:07.147", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*", "vulnerable": true, "matchCriteriaId": "7C197B6D-C48E-4D7E-A1C0-52E081E97DF0", "versionEndExcluding": "151.0.0"}, {"criteria": "cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "84A85BEB-6467-4CDB-A533-FA3AA67B1CAE", "versionEndExcluding": "151.0.0"}], "operator": "OR"}]}], "sourceIdentifier": "security@mozilla.org"}