CVE-2020-6822: Mozilla Firefox

High severity, CVSS 8.8. EPSS: 1.3% chance of exploitation in the next 30 days.

On 32-bit builds, an out of bounds write could have occurred when processing an image larger than 4 GB in <code>GMPDecodeData</code>. It is possible that with enough effort this could have been exploited to run arbitrary code. This vulnerability affects Thunderbird < 68.7.0, Firefox ESR < 68.7, and Firefox < 75.

Affected products

• Mozilla Firefox: before 75.0 (fixed in 75.0)
• Mozilla Firefox ESR: before 68.7.0 (fixed in 68.7.0)
• Mozilla Thunderbird: before 68.7.0 (fixed in 68.7.0)

Published 2020-04-24. Last modified 2026-06-17.