Site Isolation Vulnerability in Web Codecs (Firefox <154, Thunderbird <154)
CVE-2026-74981 Published on August 18, 2026

Site isolation issue in the Audio/Video: Web Codecs component
Site isolation issue in the Audio/Video: Web Codecs component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.

NVD

Vulnerability Analysis

CVE-2026-74981 can be exploited 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 high 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:
HIGH
Integrity Impact:
HIGH
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-2026-74981

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Mozilla Firefox
 
Mozilla Thunderbird
 

Affected Versions

Mozilla Firefox: Mozilla Thunderbird: