Out-of-bounds Read in Mozilla Firefox
CVE-2026-6784
Memory safety bugs present in Firefox 149 and Thunderbird 149. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability…
Vulnerability class: Buffer Overflow
EPSS: 0.000 (3.7th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H.
Affected products
- Mozilla Firefox — versions 150
- Mozilla Thunderbird — versions 150
Weakness classification (CWE)
References
- security@mozilla.org
- security@mozilla.org (Vendor Advisory)
- security@mozilla.org (Vendor Advisory)
- Memory safety bugs fixed in Firefox 150 and Thunderbird 150
Frequently asked questions
- What is CVE-2026-6784?
- CVE-2026-6784 is a high-severity vulnerability in Mozilla Firefox, classified under Out-of-bounds Read. CVSS score: 7.5/10. Published 2026-04-21.
- How severe is CVE-2026-6784?
- High severity. CVSS v3 base score is 7.5 out of 10.