linux — security advisory
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' > /sys/kernel/tracing/synthetic_events done script 2: while : do echo -n -e '\xb0' > /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+0x
- Products
- linux
- Affected versions
- Not specified
- Fixed versions
- 6.1.25-1
- CVEs
- CVE-2023-53478
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 16:03 UTC · Revision 1
Source evidence
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' > /sys/kernel/tracing/synthetic_events done script 2: while : do echo -n -e '\xb0' > /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+0x
osv:DEBIAN-CVE-2023-53478
linux
Fixed versions: 6.1.25-1
linux
Fixed versions: 6.1.25-1
linux
Fixed versions: 6.1.25-1
Complete source record
{
"id": "3fea65d22620f602189c46ec30c5894efa82322f1302d35e23e9e49337ec7cb8",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2023-53478",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2023-53478",
"summary": "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' > /sys/kernel/tracing/synthetic_events done script 2: while : do echo -n -e '\\xb0' > /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+0x",
"evidence": "osv:DEBIAN-CVE-2023-53478",
"products": [
{
"name": {
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"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
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"evidence": "/affected/0/ranges"
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{
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"severity": "medium",
"structured": {
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"aliases": [
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"metrics": [
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"type": "CVSS_V3",
"score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H"
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],
"affected": [
{
"ranges": [
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{
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"package": {
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"ecosystem": "Debian:12"
},
"database_specific": {
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},
"ecosystem_specific": {
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},
{
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{
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],
"package": {
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"ecosystem": "Debian:13"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2023-53478.json"
},
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},
{
"ranges": [
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{
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],
"package": {
"name": "linux",
"purl": "pkg:deb/debian/linux?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2023-53478.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-26T18:02:39.600150255Z",
"provider": "osv",
"upstream": [
"CVE-2023-53478"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2023-53478"
]
},
"related_cves": [
{
"value": "CVE-2023-53478",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 456518,
"published_at": "2025-10-01T12:15:50.27+00:00"
}