UBUNTU-CVE-2026-124907: Use After Free

Published Nov 12, 2026

Updated

Privilege escalation, sandbox escape due to use-after-free in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 160, Firefox ESR 153.7, Thunderbird 160, and Thunderbird 153.7.

Affected Software

10 affected components

ubuntu/mozjs52*

ubuntu/mozjs38*

ubuntu/mozjs68*

ubuntu/mozjs52*

ubuntu/mozjs102*

ubuntu/mozjs78*

ubuntu/mozjs91*

ubuntu/thunderbird*

ubuntu/mozjs102*

ubuntu/mozjs115*

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade Firefox to a version that resolves this vulnerability.
Fixed in 160
Upgrade
Upgrade Firefox ESR to a version that resolves this vulnerability.
Fixed in 153.7
Upgrade
Upgrade Thunderbird to a version that resolves this vulnerability.
Fixed in 160
Upgrade
Upgrade Thunderbird to a version that resolves this vulnerability.
Fixed in 153.7

Event History

Nov 12, 2026

CVE Published

via OSV·12:00 AM

Data Sourced

via OSV·12:00 AM

DescriptionSeverityAffected Software

Frequently Asked Questions

Which Ubuntu packages should be prioritized for remediation?

The affected package list includes thunderbird and multiple Mozilla JavaScript engine packages: mozjs38, mozjs52, mozjs68, mozjs78, mozjs91, mozjs102, and mozjs115. Prioritize systems running Thunderbird or any listed mozjs package, particularly where untrusted web content may be processed.

Which upstream releases contain the fix?

The issue was fixed in Firefox 160, Firefox ESR 153.7, Thunderbird 160, and Thunderbird 153.7.