VDB-340573 · CVE-2026-0878 · Nessus 284821

Mozilla Firefox up to 146 CanvasWebGL sandbox

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.
6.0	$5k-$25k	0.00

Summaryinfo

A vulnerability identified as critical has been detected in Mozilla Firefox up to 146. This affects an unknown part of the component CanvasWebGL. This manipulation causes sandbox. This vulnerability appears as CVE-2026-0878. The attack may be initiated remotely. There is no available exploit. You should upgrade the affected component.

Detailsinfo

A vulnerability has been found in Mozilla Firefox up to 146 and classified as critical. Affected by this vulnerability is some unknown functionality of the component CanvasWebGL. The manipulation with an unknown input leads to a sandbox vulnerability. The CWE definition for the vulnerability is CWE-265. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Sandbox escape due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability affects Firefox < 147, Firefox ESR < 140.7, Thunderbird < 147, and Thunderbird < 140.7.

The advisory is shared at bugzilla.mozilla.org. This vulnerability is known as CVE-2026-0878 since 01/13/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 01/22/2026). MITRE ATT&CK project uses the attack technique T1611 for this issue.

The vulnerability scanner Nessus provides a plugin with the ID 284821 (RHEL 8 : firefox (RHSA-2026:0667)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 147 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (284821) and CERT Bund (WID-SEC-2026-0090). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

Debian Linux
Red Hat Enterprise Linux
SUSE Linux
Oracle Linux
SUSE openSUSE
RESF Rocky Linux
Mozilla Firefox
Mozilla Firefox ESR
Mozilla Thunderbird

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: 6.3
VulDB Meta Temp Score: 6.0

VulDB Base Score: 6.3
VulDB Temp Score: 6.0
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: Sandbox
CWE: CWE-265 / CWE-264
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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

Nessus ID: 284821
Nessus Name: RHEL 8 : firefox (RHSA-2026:0667)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Firefox 147

Timelineinfo

01/13/2026 Advisory disclosed
01/13/2026 +0 days CVE reserved
01/13/2026 +0 days VulDB entry created
01/22/2026 +9 days VulDB entry last update

Sourcesinfo

Vendor: mozilla.org
Product: mozilla.org

Advisory: bugzilla.mozilla.org
Status: Confirmed

CVE: CVE-2026-0878 (🔒)
GCVE (CVE): GCVE-0-2026-0878
GCVE (VulDB): GCVE-100-340573
CERT Bund: WID-SEC-2026-0090 - Mozilla Firefox und Thunderbird: Mehrere Schwachstellen

Entryinfo

Created: 01/13/2026 15:17
Updated: 01/22/2026 10:53
Changes: 01/13/2026 15:17 (56), 01/15/2026 16:50 (2), 01/15/2026 17:13 (1), 01/15/2026 21:19 (7), 01/22/2026 10:53 (1)
Complete: 🔍
Cache ID: 216::103

If you want to get the best quality for vulnerability data then you always have to consider VulDB.