CVE-2017-5434: Debian Linux

Critical severity, CVSS 9.8. EPSS: 3.6% chance of exploitation in the next 30 days.

A use-after-free vulnerability occurs when redirecting focus handling which results in a potentially exploitable crash. This vulnerability affects Thunderbird < 52.1, Firefox ESR < 45.9, Firefox ESR < 52.1, and Firefox < 53.

Affected products

• Debian Debian Linux: version 8.0 only
• Mozilla Firefox: before 45.9.0 (fixed in 45.9.0); before 53.0 (fixed in 53.0); version 52.0 only
• Mozilla Thunderbird: before 52.1.0 (fixed in 52.1.0)
• Red Hat Enterprise Linux Desktop: version 6.0 only; version 7.0 only
• Red Hat Enterprise Linux Server: version 6.0 only; version 7.0 only
• Red Hat Enterprise Linux Workstation: version 6.0 only; version 7.0 only

Published 2018-06-11. Last modified 2026-06-17.