CVE-2026-8971

Same-origin policy bypass in the Networking: JAR component

Published May 19, 2026 CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
Description
Same-origin policy bypass in the Networking: JAR component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Mozilla thunderbird
CPEs cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
Vendors & Products Mozilla thunderbird
Type Values Removed Values Added
Description Same-origin policy bypass in the Networking: JAR component. This vulnerability was fixed in Firefox 151. Same-origin policy bypass in the Networking: JAR component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.
References
Type Values Removed Values Added
Weaknesses CWE-863
Type Values Removed Values Added
Weaknesses CWE-346
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Mozilla
Mozilla firefox
Weaknesses CWE-863
Vendors & Products Mozilla
Mozilla firefox
Type Values Removed Values Added
Description Same-origin policy bypass in the Networking: JAR component. This vulnerability was fixed in Firefox 151.
Title Same-origin policy bypass in the Networking: JAR component
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
mozilla
Published
Updated
May 19, 2026, 5:10 PM
Reserved
May 19, 2026, 12:30 PM
Status
Analyzed
Published
May 19, 2026, 2:16 PM
Modified
Jul 23, 2026, 8:10 PM