CVE-2026-74477 PUBLISHED

uprobes: Fix NULL pointer dereference in hprobe_expire()

Assigner: Linux
Reserved: 15.08.2026 Published: 15.08.2026 Updated: 15.08.2026

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.

Product Status

Vendor Linux
Product Linux
Versions Default: unaffected
  • affected from dd1a7567784e2b1f80258be04f57bcfa82c997eb to 3bd35a5e272a1b7a3fb43acad9bdc599281b13fa (excl.)
  • affected from dd1a7567784e2b1f80258be04f57bcfa82c997eb to 06c275a6c0a953ef1d763d11a6891fcc69ae2ac0 (excl.)
  • affected from dd1a7567784e2b1f80258be04f57bcfa82c997eb to cc679d7a6303e84d769f2afcde1fc51c51f127cd (excl.)
Vendor Linux
Product Linux
Versions Default: affected
  • Version 6.13 is affected
  • unaffected from 0 to 6.13 (excl.)
  • unaffected from 6.18.44 to 6.18.* (incl.)
  • unaffected from 7.1.8 to 7.1.* (incl.)
  • unaffected from 7.2-rc6 to * (incl.)

References