CVE-2023-6862: Debian Linux

High severity, CVSS 8.8. EPSS: 1% chance of exploitation in the next 30 days.

A use-after-free was identified in the `nsDNSService::Init`. This issue appears to manifest rarely during start-up. This vulnerability affects Firefox ESR < 115.6 and Thunderbird < 115.6.

Affected products

• Debian Debian Linux: version 10.0 only; version 11.0 only; version 12.0 only
• Mozilla Firefox ESR: before 115.6 (fixed in 115.6)
• Mozilla Thunderbird: before 115.6 (fixed in 115.6)

Published 2023-12-19. Last modified 2026-06-17.