CVE-2026-43409
Received Received - Intake
Kernel crash in Linux kernel after ftrace kill

Publication date: 2026-05-08

Last updated on: 2026-05-08

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: kprobes: avoid crash when rmmod/insmod after ftrace killed After we hit ftrace is killed by some errors, the kernel crash if we remove modules in which kprobe probes. BUG: unable to handle page fault for address: fffffbfff805000d PGD 817fcc067 P4D 817fcc067 PUD 817fc8067 PMD 101555067 PTE 0 Oops: Oops: 0000 [#1] SMP KASAN PTI CPU: 4 UID: 0 PID: 2012 Comm: rmmod Tainted: G W OE Tainted: [W]=WARN, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE RIP: 0010:kprobes_module_callback+0x89/0x790 RSP: 0018:ffff88812e157d30 EFLAGS: 00010a02 RAX: 1ffffffff805000d RBX: dffffc0000000000 RCX: ffffffff86a8de90 RDX: ffffed1025c2af9b RSI: 0000000000000008 RDI: ffffffffc0280068 RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1025c2af9a R10: ffff88812e157cd7 R11: 205d323130325420 R12: 0000000000000002 R13: ffffffffc0290488 R14: 0000000000000002 R15: ffffffffc0280040 FS: 00007fbc450dd740(0000) GS:ffff888420331000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffffbfff805000d CR3: 000000010f624000 CR4: 00000000000006f0 Call Trace: <TASK> notifier_call_chain+0xc6/0x280 blocking_notifier_call_chain+0x60/0x90 __do_sys_delete_module.constprop.0+0x32a/0x4e0 do_syscall_64+0x5d/0xfa0 entry_SYSCALL_64_after_hwframe+0x76/0x7e This is because the kprobe on ftrace does not correctly handles the kprobe_ftrace_disabled flag set by ftrace_kill(). To prevent this error, check kprobe_ftrace_disabled in __disarm_kprobe_ftrace() and skip all ftrace related operations.
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Meta Information
Published
2026-05-08
Last Modified
2026-05-08
Generated
2026-05-09
AI Q&A
2026-05-08
EPSS Evaluated
N/A
NVD
CVE-2026-43409
EUVD
EUVD-2026-28715
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *
Helpful Resources
Exploitability
CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-UNKNOWN
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability exists in the Linux kernel's kprobes subsystem related to ftrace. When ftrace is killed due to some errors, the kernel crashes if modules that have kprobe probes are removed. The root cause is that the kprobe on ftrace does not correctly handle the kprobe_ftrace_disabled flag set by ftrace_kill(). This leads to a page fault and kernel crash during module removal operations.

The fix involves checking the kprobe_ftrace_disabled flag in the __disarm_kprobe_ftrace() function and skipping all ftrace related operations if the flag is set, preventing the crash.


How can this vulnerability impact me? :

This vulnerability can cause the Linux kernel to crash when removing kernel modules that have kprobe probes after ftrace has been killed by errors. Such crashes can lead to system instability, unexpected downtime, and potential loss of data or service availability.


How can this vulnerability be detected on my network or system? Can you suggest some commands?

This vulnerability can be detected by monitoring for kernel crashes or oops messages related to kprobes and ftrace when removing kernel modules.

Specifically, look for kernel logs containing messages like "BUG: unable to handle page fault for address" and "Oops: 0000 [#1] SMP KASAN PTI" with references to kprobes_module_callback and rmmod commands.

You can check kernel logs using commands such as:

  • dmesg | grep -i 'kprobes_module_callback'
  • journalctl -k | grep -i 'Oops'
  • journalctl -k | grep -i 'rmmod'
  • grep -i 'BUG' /var/log/kern.log

What immediate steps should I take to mitigate this vulnerability?

To mitigate this vulnerability, avoid removing kernel modules (rmmod) or inserting modules (insmod) after ftrace has been killed or encountered errors.

Ensure that the kernel is updated with the patch that checks the kprobe_ftrace_disabled flag in __disarm_kprobe_ftrace() and skips all ftrace related operations to prevent crashes.

If updating the kernel immediately is not possible, monitor kernel logs closely for related crashes and avoid operations that trigger this issue.


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