Same-Origin Policy Bypass in Firefox by Mozilla
CVE-2026-3846

6.5MEDIUM

Key Information:

Vendor

Mozilla
Status
Firefox
Vendor
CVE Published:
10 March 2026

What is CVE-2026-3846?

A vulnerability has been identified in the CSS Parsing and Computation component of Firefox, allowing an attacker to bypass the same-origin policy. This can lead to unauthorized access to sensitive data, affecting the integrity of web applications. Users of Firefox versions below 148.0.2 are at risk and should consider upgrading to the latest version to mitigate the issues associated with this vulnerability.

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Affected Version(s)

Firefox < 148.0.2

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2018400
https://www.mozilla.org/security/advisories/mfsa2026-19/

CVSS V3.1

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

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Jun Yang of Tencent Zhuque Lab
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