NULL pointer dereference in Mozilla Firefox and Firefox for Android - CVE-2026-6778
Published: April 21, 2026
Vulnerability identifier: #VU126686
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-6778
CWE-ID: CWE-476
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to an invalid pointer dereference in the Audio/Video: Playback component when processing media playback. A remote attacker can supply crafted media to cause a denial of service.
Affected software
Mozilla Firefox
Firefox for Android
Mozilla Thunderbird
Firefox for Android
Mozilla Thunderbird
How to mitigate CVE-2026-6778
Install security update from vendor's website.
Mozilla Firefox - update to 150.0
Firefox for Android - update to 150.0
Mozilla Thunderbird - update to 150.0
Firefox for Android - update to 150.0
Mozilla Thunderbird - update to 150.0