CVE-2017-5430: Mozilla Firefox

Critical severity, CVSS 9.8. EPSS: 3% chance of exploitation in the next 30 days.

Memory safety bugs were reported in Firefox 52, Firefox ESR 52, and Thunderbird 52. Some of these bugs showed evidence of memory corruption and we presume that with enough effort that some of these could be exploited to run arbitrary code. This vulnerability affects Thunderbird < 52.1, Firefox ESR < 52.1, and Firefox < 53.

Affected products

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

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