uprobes: Fix NULL pointer dereference in hprobe_expire()
Forking a task that has a pending uretprobe can oops the kernel with a
NULL pointer dereference in the clone() path:
BUG: kernel NULL pointer dereference, address: 0000000000000018
Oops: 0002 [#1] SMP NOPTI
RIP: 0010:hprobe_expire
CR2: 0000000000000018
Call Trace:
uprobe_copy_process
copy_process
kernel_clone
__x64_sys_clone
do_syscall_64
entry_SYSCALL_64_after_hwframe
This was found on real hosts on Meta fleet.
I've got the impression that this is what is happening:
CPU 1 CPU 2 (traced task)
----- -------------------
hit uprobe, prepare_uretprobe():
hprobe LEASED, refcount >= 1
uprobe_unregister()
put_uprobe(): refcount -> 0
fork() -> dup_utask()
hprobe_expire(hprobe, true)
try_get_uprobe() -> NULL
get_uprobe(NULL) <-- Oops
Only take the extra reference when the uprobe is non-NULL; a NULL means
it is gone and is the correct value to return.
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No vendor fix or workaround currently provided.
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Sat, 15 Aug 2026 16:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-758 |
Sat, 15 Aug 2026 12:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: uprobes: Fix NULL pointer dereference in hprobe_expire() Forking a task that has a pending uretprobe can oops the kernel with a NULL pointer dereference in the clone() path: BUG: kernel NULL pointer dereference, address: 0000000000000018 Oops: 0002 [#1] SMP NOPTI RIP: 0010:hprobe_expire CR2: 0000000000000018 Call Trace: uprobe_copy_process copy_process kernel_clone __x64_sys_clone do_syscall_64 entry_SYSCALL_64_after_hwframe This was found on real hosts on Meta fleet. I've got the impression that this is what is happening: CPU 1 CPU 2 (traced task) ----- ------------------- hit uprobe, prepare_uretprobe(): hprobe LEASED, refcount >= 1 uprobe_unregister() put_uprobe(): refcount -> 0 fork() -> dup_utask() hprobe_expire(hprobe, true) try_get_uprobe() -> NULL get_uprobe(NULL) <-- Oops Only take the extra reference when the uprobe is non-NULL; a NULL means it is gone and is the correct value to return. | |
| Title | uprobes: Fix NULL pointer dereference in hprobe_expire() | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-08-15T12:27:11.938Z
Reserved: 2026-08-15T05:44:03.903Z
Link: CVE-2026-74477
No data.
Status : Received
Published: 2026-08-15T13:17:52.497
Modified: 2026-08-15T13:17:52.497
Link: CVE-2026-74477
No data.
OpenCVE Enrichment
Updated: 2026-08-15T15:45:06Z