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.
Advisories
Source ID Title
Ubuntu USN Ubuntu USN USN-9019-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-9020-1 Linux kernel vulnerabilities
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Fri, 21 Aug 2026 22:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-758

Thu, 20 Aug 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-476
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate


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

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-08-17T05:20:09.952Z

Reserved: 2026-08-15T05:44:03.903Z

Link: CVE-2026-74477

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-15T13:17:52.497

Modified: 2026-08-17T06:19:43.777

Link: CVE-2026-74477

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-08-15T00:00:00Z

Links: CVE-2026-74477 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-08-21T23:45:03Z

Weaknesses