What is CVE-2026-6780?

CVE-2026-6780 is a high-severity vulnerability in Mozilla Firefox, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-04-21.

How severe is CVE-2026-6780?

High severity. CVSS v3 base score is 7.5 out of 10.

Resource exhaustion in Mozilla Firefox

CVE-2026-6780

Denial-of-service in the Audio/Video: Playback component. This vulnerability was fixed in Firefox 150 and Thunderbird 150.

Vulnerability class: DoS (Denial of Service)

EPSS: 0.003 (21.4th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Mozilla Firefox — versions 150
Mozilla Thunderbird — versions 150

Weakness classification (CWE)

CWE-400 — Uncontrolled Resource Consumption

References

security@mozilla.org (Permissions Required)
security@mozilla.org (Vendor Advisory)
security@mozilla.org (Vendor Advisory)

Frequently asked questions

What is CVE-2026-6780?: CVE-2026-6780 is a high-severity vulnerability in Mozilla Firefox, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-04-21.
How severe is CVE-2026-6780?: High severity. CVSS v3 base score is 7.5 out of 10.