CVE-2019-17011: Canonical Ubuntu Linux

High severity, CVSS 7.5. EPSS: 1.5% chance of exploitation in the next 30 days.

Under certain conditions, when retrieving a document from a DocShell in the antitracking code, a race condition could cause a use-after-free condition and a potentially exploitable crash. This vulnerability affects Thunderbird < 68.3, Firefox ESR < 68.3, and Firefox < 71.

Affected products

• Canonical Ubuntu Linux: version 16.04 only; version 18.04 only; version 19.10 only
• Mozilla Firefox: before 71.0 (fixed in 71.0)
• Mozilla Firefox ESR: before 68.3 (fixed in 68.3)
• Mozilla Thunderbird: before 68.3 (fixed in 68.3)
• Opensuse Leap: version 15.1 only

Published 2020-01-08. Last modified 2026-06-17.