VDB-391634 · CVE-2026-74981 · GCVE-0-2026-74981

Mozilla Firefox up to 153.0/153 Web Codecs isolation

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.0	$5k-$25k	0.40

Summaryinfo

A vulnerability described as critical has been identified in Mozilla Firefox up to 153.0/153. Affected by this issue is some unknown functionality of the component Web Codecs. Such manipulation leads to isolation. This vulnerability is traded as CVE-2026-74981. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in Mozilla Firefox up to 153.0/153. It has been rated as critical. Affected by this issue is an unknown code block of the component Web Codecs. The manipulation with an unknown input leads to a isolation vulnerability. Using CWE to declare the problem leads to CWE-653. The product does not properly compartmentalize or isolate functionality, processes, or resources that require different privilege levels, rights, or permissions. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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

The advisory is available at bugzilla.mozilla.org. This vulnerability is handled as CVE-2026-74981 since 08/17/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 08/18/2026).

Upgrading to version 153.1 or 154 eliminates this vulnerability.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

Web Browser

Vendor

Mozilla

Name

Firefox

Version

License

open-source

Website

Vendor: https://www.mozilla.org/
Product: https://www.mozilla.org/en-US/firefox/

CPE 2.3info

🔒

CPE 2.2info

🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 7.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Isolation
CWE: CWE-653
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Firefox 153.1/154

Timelineinfo

08/17/2026 CVE reserved
08/18/2026 +1 days Advisory disclosed
08/18/2026 +0 days VulDB entry created
08/18/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: mozilla.org
Product: mozilla.org

Advisory: bugzilla.mozilla.org
Status: Confirmed

CVE: CVE-2026-74981 (🔒)
GCVE (CVE): GCVE-0-2026-74981
GCVE (VulDB): GCVE-100-391634

Entryinfo

Created: 08/18/2026 15:32
Changes: 08/18/2026 15:32 (57)
Complete: 🔍
Cache ID: 216::103