CVE-2026-0878

Sandbox escape due to incorrect boundary conditions in the Graphics: CanvasWebGL component

Severity Score

8.0

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

Track

*SSVC

Descriptions

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

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

Multiple security issues have been found in the Mozilla Firefox web browser, which could potentially result in the execution of arbitrary code, sandbox escape, information disclosure or spoofing. For the oldstable distribution (bookworm), these problems have been fixed in version 140.7.0esr-1~deb12u1. For the stable distribution (trixie), these problems have been fixed in version 140.7.0esr-1~deb13u1.

*Credits: Oskar L

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

High

Integrity

High

Availability

None

Attack Vector

Network

Attack Complexity

High

Authentication

None

Confidentiality

Complete

Integrity

Complete

Availability

None

* Common Vulnerability Scoring System

SSVC

Decision:Track

Exploitation

None

Automatable

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

2026-01-13 CVE Reserved
2026-01-13 CVE Published
2026-03-22 EPSS Updated
2026-04-13 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-20: Improper Input Validation
CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer

CAPEC

References (5)

URL	Tag	Source
https://bugzilla.mozilla.org/show_bug.cgi?id=2003989
https://www.mozilla.org/security/advisories/mfsa2026-01
https://www.mozilla.org/security/advisories/mfsa2026-03
https://www.mozilla.org/security/advisories/mfsa2026-04
https://www.mozilla.org/security/advisories/mfsa2026-05

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Mozilla Search vendor "Mozilla"		Firefox Search vendor "Mozilla" for product "Firefox"				*		-		Affected
Mozilla Search vendor "Mozilla"		Firefox Esr Search vendor "Mozilla" for product "Firefox Esr"				*		-		Affected
Centos Search vendor "Centos"		Centos Search vendor "Centos" for product "Centos"				*		-		Affected
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				*		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				*		-		Affected
Redhat Search vendor "Redhat"		Enterprise Linux Search vendor "Redhat" for product "Enterprise Linux"				*		-		Affected
Slackware Search vendor "Slackware"		Slackware Linux Search vendor "Slackware" for product "Slackware Linux"				*		-		Affected
Suse Search vendor "Suse"		Sles-ltss-extended-security Search vendor "Suse" for product "Sles-ltss-extended-security"				*		-		Affected
Suse Search vendor "Suse"		Sles-ltss Search vendor "Suse" for product "Sles-ltss"				*		-		Affected
Suse Search vendor "Suse"		Sles Search vendor "Suse" for product "Sles"				*		-		Affected