CVE-2026-8950

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2026-8950
Same-origin policy bypass in the Networking: HTTP component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

9.3 /10

CVSS v3 : CRITICAL

V3 Legend

Vector :

Exploitability : 2.8 / Impact : 5.8

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact NONE

Scope CHANGED

References
Link Resource
https://bugzilla.mozilla.org/show_bug.cgi?id=1965430 Permissions Required
https://www.mozilla.org/security/advisories/mfsa2026-46/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-48/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-50/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-51/ Vendor Advisory
Configurations

Configuration 1 (hide)

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

20 May 2026, 15:00

Type Values Removed Values Added
First Time Mozilla thunderbird
Mozilla
Mozilla firefox
CPE cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
References () https://bugzilla.mozilla.org/show_bug.cgi?id=1965430 - () https://bugzilla.mozilla.org/show_bug.cgi?id=1965430 - Permissions Required
References () https://www.mozilla.org/security/advisories/mfsa2026-46/ - () https://www.mozilla.org/security/advisories/mfsa2026-46/ - Vendor Advisory
References () https://www.mozilla.org/security/advisories/mfsa2026-48/ - () https://www.mozilla.org/security/advisories/mfsa2026-48/ - Vendor Advisory
References () https://www.mozilla.org/security/advisories/mfsa2026-50/ - () https://www.mozilla.org/security/advisories/mfsa2026-50/ - Vendor Advisory
References () https://www.mozilla.org/security/advisories/mfsa2026-51/ - () https://www.mozilla.org/security/advisories/mfsa2026-51/ - Vendor Advisory

19 May 2026, 18:16

Type Values Removed Values Added
References
  • () https://www.mozilla.org/security/advisories/mfsa2026-50/ -
  • () https://www.mozilla.org/security/advisories/mfsa2026-51/ -
Summary (en) Same-origin policy bypass in the Networking: HTTP component. This vulnerability was fixed in Firefox 151 and Firefox ESR 140.11. (en) Same-origin policy bypass in the Networking: HTTP component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

19 May 2026, 17:16

Type Values Removed Values Added
CWE CWE-346
CVSS v2 : unknown
v3 : unknown 		v2 : unknown
v3 : 9.3

19 May 2026, 14:16

Type Values Removed Values Added
New CVE
Information

Published : 2026-05-19 14:16

Updated : 2026-05-20 15:00

NVD link : CVE-2026-8950

Mitre link : CVE-2026-8950

CVE.ORG link : CVE-2026-8950

JSON object : View

Products Affected

mozilla

  • firefox
  • thunderbird
CWE
CWE-346

Origin Validation Error