CVE-2023-4585: Mozilla Firefox

High severity, CVSS 8.8. EPSS: 0.8% chance of exploitation in the next 30 days.

Memory safety bugs present in Firefox 116, Firefox ESR 115.1, and Thunderbird 115.1. 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 affects Firefox < 117, Firefox ESR < 115.2, and Thunderbird < 115.2.

Affected products

• Mozilla Firefox: before 117.0 (fixed in 117.0)
• Mozilla Firefox ESR: before 115.2 (fixed in 115.2)
• Mozilla Thunderbird: before 115.2 (fixed in 115.2)

Published 2023-09-11. Last modified 2026-06-17.