CVE-2019-19039: Canonical Ubuntu Linux

Medium severity, CVSS 5.5. EPSS: 0.7% chance of exploitation in the next 30 days.

__btrfs_free_extent in fs/btrfs/extent-tree.c in the Linux kernel through 5.3.12 calls btrfs_print_leaf in a certain ENOENT case, which allows local users to obtain potentially sensitive information about register values via the dmesg program. NOTE: The BTRFS development team disputes this issues as not being a vulnerability because “1) The kernel provide facilities to restrict access to dmesg - dmesg_restrict=1 sysctl option. So it's really up to the system administrator to judge whether dmesg access shall be disallowed or not. 2) WARN/WARN_ON are widely used macros in the linux kernel. If this CVE is considered valid this would mean there are literally thousands CVE lurking in the kernel - something which clearly is not the case.

Affected products

• Canonical Ubuntu Linux: version 14.04 only; version 16.04 only; version 18.04 only
• Debian Debian Linux: version 9.0 only
• Linux Linux Kernel: up to and including 5.3.12

Published 2019-11-21. Last modified 2026-06-17.