Same-Origin Policy Bypass in Firefox by Mozilla
CVE-2026-8971

6.5MEDIUM

Key Information:

Vendor

Mozilla
Status
Firefox
Thunderbird
Vendor
CVE Published:
19 May 2026

What is CVE-2026-8971?

A significant vulnerability in Mozilla's Firefox web browser allows attackers to bypass the same-origin policy due to flaws in the Networking: JAR component. This can result in unauthorized data access and potential exploitation of users' sessions. Mozilla addressed this issue in version 151, ensuring enhanced protection for users against security risks associated with this vulnerability.

Affected Version(s)

Firefox 151

Thunderbird 151

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2032604
https://www.mozilla.org/security/advisories/mfsa2026-46/
https://www.mozilla.org/security/advisories/mfsa2026-50/

CVSS V3.1

Score:
6.5
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Surya Dev Singh
.