High 7.8Published Sep 5, 2025

CVE-2025-39683tracing: Limit access to parser->buffer when trace_get_user failed

Updated under an hour ago (Oct 27, 2026, 5:10 AM ET)

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Exploited in the last 30 days

In the Linux kernel, the following vulnerability has been resolved: tracing: Limit access to parser->buffer when trace_get_user failed When the length of the string written to set_ftrace_filter exceeds FTRACE_BUFF_MAX, the following KASAN alarm will be triggered: BUG: KASAN: slab-out-of-bounds in strsep+0x18c/0x1b0 Read of size 1 at addr ffff0000d00bd5ba by task ash/165 CPU: 1 UID: 0 PID: 165 Comm: ash Not tainted 6.16.0-g6bcdbd62bd56-dirty Hardware name: linux,dummy-virt (DT) Call trace: show_stack+0x34/0x50 (C) dump_stack_lvl+0xa0/0x158 print_address_description.constprop.0+0x88/0x398 print_report+0xb0/0x280 kasan_report+0xa4/0xf0 __asan_report_load1_noabort+0x20/0x30 strsep+0x18c/0x1b0 ftrace_process_regex.isra.0+0x100/0x2d8 ftrace_regex_release+0x484/0x618 __fput+0x364/0xa58 ____fput+0x28/0x40 task_work_run+0x154/0x278 do_notify_resume+0x1f0/0x220 el0_svc+0xec/0xf0 el0t_64_sync_handler+0xa0/0xe8 el0t_64_sync+0x1ac/0x1b0 The reason is that trace_get_user will fail when processing a string longer than FTRACE_BUFF_MAX, but not set the end of parser->buffer to 0. Then an OOB access will be triggered in ftrace_regex_release-> ftrace_process_regex->strsep->strpbrk. We can solve this problem by limiting access to parser->buffer when trace_get_user failed.

CVSS: 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 15, 2026
First seen by InfoSec Signals: Oct 14, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from 634684d79733124f7470b226b0f42aada4426b07 before b842ef39c2ad6156c13afdec25ecc6792a9b67b9; from 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 before 41b838420457802f21918df66764b6fbf829d330; from 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 before 418b448e1d7470da9d4d4797f71782595ee69c49; from 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 before 58ff8064cb4c7eddac4da1a59da039ead586950a; from 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 before d0c68045b8b0f3737ed7bd6b8c83b7887014adee; from 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 before 3079517a5ba80901fe828a06998da64b9b8749be; 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 builds before 6a909ea83f226803ea0e718f6e88613df9234d58; 24cd31752f47699b89b4b3471155c8e599a1a23a; and 14 more ranges	CNA record
Siemens SIMATIC CN 4100 siemens:simatic_cn_4100 (from the name)	before V5.0	CISA ADP
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.5	CISA ADP
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name)	from V3.1.5	CISA ADP
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.5	CISA ADP
linux linux_kernel linux:linux_kernel	from 4.4.269 before 4.5; from 4.9.269 before 4.10; from 4.14.233 before 4.15; from 4.19.191 before 4.20; from 5.4.118 before 5.5; from 5.10.36 before 5.10.241; from 5.11.20 before 5.12; from 5.12.3 before 5.15.190; and 6 more ranges	NVD
debian debian_linux debian:debian_linux	11.0	NVD

References

References

https://git.kernel.org/stable/c/b842ef39c2ad6156c13afdec25ecc6792a9b67b9	patch
https://git.kernel.org/stable/c/41b838420457802f21918df66764b6fbf829d330	patch
https://git.kernel.org/stable/c/418b448e1d7470da9d4d4797f71782595ee69c49	patch
https://git.kernel.org/stable/c/58ff8064cb4c7eddac4da1a59da039ead586950a	patch
https://git.kernel.org/stable/c/d0c68045b8b0f3737ed7bd6b8c83b7887014adee	patch
https://git.kernel.org/stable/c/3079517a5ba80901fe828a06998da64b9b8749be	patch
https://git.kernel.org/stable/c/6a909ea83f226803ea0e718f6e88613df9234d58	patch
https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html	third-party-advisory
https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html	third-party-advisory
https://cert-portal.siemens.com/productcert/html/ssa-032379.html
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The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.