CVE-2023-4056: Debian Linux

Critical severity, CVSS 9.8. EPSS: 0.9% chance of exploitation in the next 30 days.

Memory safety bugs present in Firefox 115, Firefox ESR 115.0, Firefox ESR 102.13, Thunderbird 115.0, and Thunderbird 102.13. 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 < 116, Firefox ESR < 102.14, and Firefox ESR < 115.1.

Affected products

• Debian Debian Linux: version 10.0 only; version 11.0 only; version 12.0 only
• Mozilla Firefox: before 116.0 (fixed in 116.0); from 102.0, before 102.14 (fixed in 102.14); from 115.0, before 115.1 (fixed in 115.1)

Published 2023-08-01. Last modified 2026-06-17.