{"id":"DEBIAN-CVE-2023-53478","details":"In the Linux kernel, the following vulnerability has been resolved:  tracing/synthetic: Fix races on freeing last_cmd  Currently, the \"last_cmd\" variable can be accessed by multiple processes asynchronously when multiple users manipulate synthetic_events node at the same time, it could lead to use-after-free or double-free.  This patch add \"lastcmd_mutex\" to prevent \"last_cmd\" from being accessed asynchronously.  ================================================================  It's easy to reproduce in the KASAN environment by running the two scripts below in different shells.  script 1:         while :         do                 echo -n -e '\\x88' \u003e /sys/kernel/tracing/synthetic_events         done  script 2:         while :         do                 echo -n -e '\\xb0' \u003e /sys/kernel/tracing/synthetic_events         done  ================================================================ double-free scenario:      process A                       process B -------------------               --------------- 1.kstrdup last_cmd                                   2.free last_cmd 3.free last_cmd(double-free)  ================================================================ use-after-free scenario:      process A                       process B -------------------               --------------- 1.kstrdup last_cmd                                   2.free last_cmd 3.tracing_log_err(use-after-free)  ================================================================  Appendix 1. KASAN report double-free:  BUG: KASAN: double-free in kfree+0xdc/0x1d4 Free of addr ***** by task sh/4879 Call trace:         ...         kfree+0xdc/0x1d4         create_or_delete_synth_event+0x60/0x1e8         trace_parse_run_command+0x2bc/0x4b8         synth_events_write+0x20/0x30         vfs_write+0x200/0x830         ...  Allocated by task 4879:         ...         kstrdup+0x5c/0x98         create_or_delete_synth_event+0x6c/0x1e8         trace_parse_run_command+0x2bc/0x4b8         synth_events_write+0x20/0x30         vfs_write+0x200/0x830         ...  Freed by task 5464:         ...         kfree+0xdc/0x1d4         create_or_delete_synth_event+0x60/0x1e8         trace_parse_run_command+0x2bc/0x4b8         synth_events_write+0x20/0x30         vfs_write+0x200/0x830         ...  ================================================================ Appendix 2. KASAN report use-after-free:  BUG: KASAN: use-after-free in strlen+0x5c/0x7c Read of size 1 at addr ***** by task sh/5483 sh: CPU: 7 PID: 5483 Comm: sh         ...         __asan_report_load1_noabort+0x34/0x44         strlen+0x5c/0x7c         tracing_log_err+0x60/0x444         create_or_delete_synth_event+0xc4/0x204         trace_parse_run_command+0x2bc/0x4b8         synth_events_write+0x20/0x30         vfs_write+0x200/0x830         ...  Allocated by task 5483:         ...         kstrdup+0x5c/0x98         create_or_delete_synth_event+0x80/0x204         trace_parse_run_command+0x2bc/0x4b8         synth_events_write+0x20/0x30         vfs_write+0x200/0x830         ...  Freed by task 5480:         ...         kfree+0xdc/0x1d4         create_or_delete_synth_event+0x74/0x204         trace_parse_run_command+0x2bc/0x4b8         synth_events_write+0x20/0x30         vfs_write+0x200/0x830         ...","modified":"2026-09-15T09:02:45.338702767Z","published":"2025-10-01T12:15:50.270Z","upstream":["CVE-2023-53478"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2023-53478"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:12","purl":"pkg:deb/debian/linux?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.25-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2023-53478.json"}},{"package":{"name":"linux","ecosystem":"Debian:13","purl":"pkg:deb/debian/linux?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.25-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2023-53478.json"}},{"package":{"name":"linux","ecosystem":"Debian:14","purl":"pkg:deb/debian/linux?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.25-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2023-53478.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}