Same-Origin Policy Bypass in Firefox Networking Component
CVE-2026-8948

9.1CRITICAL

Key Information:

Vendor

Mozilla
Status
Firefox
Thunderbird
Vendor
CVE Published:
19 May 2026

What is CVE-2026-8948?

A vulnerability exists in the Networking component of Firefox that allows an attacker to bypass the same-origin policy. This can potentially enable unauthorized access to sensitive user information across different sites. Mozilla promptly addressed this security risk in Firefox version 151, urging users to update to maintain the integrity and security of their browsing experience.

Affected Version(s)

Firefox 151

Thunderbird 151

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2038803
https://www.mozilla.org/security/advisories/mfsa2026-46/
https://www.mozilla.org/security/advisories/mfsa2026-50/

CVSS V3.1

Score:
9.1
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

satyamasd
.