Site Isolation Vulnerability in Firefox Graphics Component
CVE-2026-16398

7.5HIGH

Key Information:

Vendor

Mozilla
Status
Firefox
Thunderbird
Vendor
CVE Published:
21 July 2026

What is CVE-2026-16398?

This vulnerability involves a site isolation flaw within the graphics component of Firefox, which can potentially expose user data to malicious sites. It was effectively addressed in Firefox version 153, ensuring enhanced protection against such threats. Users are urged to update their browsers to mitigate risks associated with this issue.

Affected Version(s)

Firefox 153

Thunderbird 153

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2048345
https://www.mozilla.org/security/advisories/mfsa2026-68/
https://www.mozilla.org/security/advisories/mfsa2026-71/

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
High
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

stevej
.