Site isolation flaw in Firefox Reader Mode (pre156/ESR153.3): CVE-2026-92068 September 2026

Site isolation flaw in Firefox Reader Mode (pre156/ESR153.3)
CVE-2026-92068 Published on September 15, 2026

Site isolation issue in the Reader Mode component
Site isolation issue in the Reader Mode component. This vulnerability was fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird 153.3.

Vulnerability Analysis

CVE-2026-92068 is exploitable with network access, requires user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a small impact on confidentiality and integrity, and no impact on availability.

Attack Vector:

NETWORK

Attack Complexity:

LOW

Privileges Required:

NONE

User Interaction:

REQUIRED

Scope:

UNCHANGED

Confidentiality Impact:

LOW

Integrity Impact:

LOW

Availability Impact:

NONE

Weakness Type

Origin Validation Error

The software does not properly verify that the source of data or communication is valid.

Products Associated with CVE-2026-92068

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Affected Versions

Version 153.3, <= 153.* is unaffected.

Version 156, <= * is unaffected.