Is CVE-2025-39683 being actively exploited?

It is not currently in CISA's KEV catalog. Its EPSS exploitation probability is 0%.

What products does CVE-2025-39683 affect?

Tracked products affected include Debian, Linux Kernel. Check the version you run to see whether it is affected.

How do I fix CVE-2025-39683?

Apply the vendor fix promptly. An official patch or advisory is available. Upgrade affected products to a fixed version.

← All products

CVE-2025-39683

Q: What is CVE-2025-39683?

CVE-2025-39683 is a high-severity software vulnerability (Out-of-bounds read) with a CVSS score of 7.8. 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

HIGH severity · CVSS 7.8 · Out-of-bounds read

7.8CVSS HIGH

Summary

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.

Impact & exploitability

Attack vectorLocal

Attack complexityLow

Privileges requiredLow

User interactionNone

Confidentiality impactHigh

Integrity impactHigh

Availability impactHigh

Exploit probability (EPSS)0%

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products we track (2)

Debian Linux Kernel

Recommendation

Apply the vendor fix promptly. Open any affected product above for its exact safe version.

Official patch: https://git.kernel.org/stable/c/3079517a5ba80901fe828a06998da64b9b8749be ↗

CVE-2025-39683

Summary

Impact & exploitability

Affected products we track (2)

Recommendation

Additional information