CVE-2026-16398: Site isolation issue in the Graphics component

Published Jul 21, 2026
·
Updated

Site isolation issue in the Graphics component. This vulnerability was fixed in Firefox 153 and Thunderbird 153.

Affected Software

5 affected componentsFixes available
Mozilla Firefox<=153
Mozilla Firefox<153
153
Mozilla Thunderbird<153
153
Mozilla Firefox<153.0.0
Mozilla Thunderbird<153.0

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 153
  2. Upgrade

    Upgrade Firefox to a version that resolves this vulnerability.

    Fixed in 153
  3. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 153

Event History

Jul 21, 2026
CVE Published
via Mozilla·12:00 AM
Data Sourced
via Mozilla·12:00 AM
DescriptionSeverityAffected Software
Updated
via Mozilla·12:00 AM
Affected Software
CVE Published
via MITRE·12:38 PM
Data Sourced
via MITRE·12:38 PM
Description
Data Sourced
via NVD·01:17 PM
DescriptionSeverityWeaknessAffected Software

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

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Frequently Asked Questions

1

What is the severity of CVE-2026-16398?

CVE-2026-16398 has a severity rating of high at 7.5 according to the CVSS 3.1 score.

2

How do I fix CVE-2026-16398?

To fix CVE-2026-16398, update to Firefox version 153 or Thunderbird version 153 or later.

3

What type of vulnerability is CVE-2026-16398?

CVE-2026-16398 is classified as an infoleak vulnerability due to site isolation issues in the Graphics component.

4

When was CVE-2026-16398 published?

CVE-2026-16398 was published on July 21, 2026.

5

Which software is affected by CVE-2026-16398?

CVE-2026-16398 affects Mozilla Firefox and Mozilla Thunderbird.

Company

Resources

Contact

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