Bug 2513257 (CVE-2026-68378)

Summary: CVE-2026-68378 kernel: dpll: fix NULL pointer dereference in dpll_msg_add_pin_ref_sync()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Priority: low    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's dpll subsystem. A local user could trigger a null pointer dereference in the `dpll_msg_add_pin_ref_sync()` function when a `dpll_pin` is shared across multiple `dpll_device` instances and those devices are being unregistered. This vulnerability can lead to a system crash, resulting in a Denial of Service (DoS).
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-08-10 12:27:30 UTC 
In the Linux kernel, the following vulnerability has been resolved:

dpll: fix NULL pointer dereference in dpll_msg_add_pin_ref_sync()

When a dpll_pin is shared across multiple dpll_device instances and
those devices are being unregistered (e.g. during driver module removal),
a NULL pointer dereference can occur in dpll_msg_add_pin_ref_sync().

This happens under the following conditions:
 - A pin is registered with two or more dpll devices (dpll_A, dpll_B)
 - The pin has ref_sync pairs with other pins
 - During unregistration of dpll_A's pins, a ref_sync partner pin is
   unregistered first, removing it from dpll_A->pin_refs
 - But since the partner pin is still registered with dpll_B, its
   dpll_refs is not empty, so dpll_pin_ref_sync_pair_del() does NOT
   run and the partner stays in the pin's ref_sync_pins xarray
 - When the pin itself is then unregistered from dpll_A, the delete
   notification calls dpll_msg_add_pin_ref_sync() which finds the
   partner in ref_sync_pins, passes dpll_pin_available() (partner is
   still registered with dpll_B), but dpll_pin_on_dpll_priv(dpll_A,
   partner) returns NULL because partner was already removed from
   dpll_A->pin_refs
 - The NULL priv pointer is passed to the driver's ref_sync_get
   callback, which dereferences it

 BUG: kernel NULL pointer dereference, address: 0000000000000034
 Oops: Oops: 0000 [#1] SMP NOPTI
 RIP: 0010:zl3073x_dpll_input_pin_ref_sync_get+0x73/0x80 [zl3073x]
 Call Trace:
  dpll_msg_add_pin_ref_sync+0xb8/0x200
  dpll_cmd_pin_get_one+0x3b6/0x4b0
  dpll_pin_event_send+0x72/0x140
  __dpll_pin_unregister+0x5a/0x2b0
  dpll_pin_unregister+0x49/0x70

Fix this by skipping ref_sync pins whose priv pointer cannot be resolved
for the current dpll device.