In the Linux kernel, the following vulnerability has been resolved:
scsi: qla2xxx: Fix cs84xx use-after-free on host teardown
qla84xx_put_chip() drops the last reference to ha->cs84xx and frees it via
__qla84xx_chip_release() without clearing ha->cs84xx. During teardown it ran
before scsi_remove_host(), which is what removes the 84xx_fw_version host
sysfs attribute. A concurrent read of that attribute in the window between
the two calls executes qla24xx_84xx_fw_version_show(), which dereferences
the freed ha->cs84xx, resulting in a use-after-free.
Move qla84xx_put_chip() to after scsi_remove_host() in both
qla2x00_remove_one() and qla2x00_disable_board_on_pci_error(). Once
scsi_remove_host() returns, the sysfs attribute is gone and kernfs has
drained any in-flight show(), so no reader can touch cs84xx; the put still
runs before the host and ha are freed.
CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS Score: 7.8
AV:L - The UAF is reached from qla24xx_84xx_fw_version_show() on the SCSI host sysfs attribute while qla2x00_remove_one() tears down a QLogic ISP8432 (84xx) HBA. That is a local sysfs/PCI-unbind path, not a network or Fibre Channel frame handler.
AC:L - An attacker can loop-read /sys/class/scsi_host/hostN/84xx_fw_version while teardown runs. qla84xx_put_chip() freed cs84xx before scsi_remove_host(), leaving a large window through timer stop, DMA free, workqueue destroy, and fc_remove_host(). The attacker controls the sysfs side and can retry.
PR:L - 84xx_fw_version is DEVICE_ATTR(..., S_IRUGO) with no capable() check in qla24xx_84xx_fw_version_show(), so an unprivileged local user can read it. Per CNA driver-removal UAF precedent, concurrent PCI unbind or rmmod does not require the attacker to hold init-namespace root.
UI:N - The attacker performs their own sysfs reads against 84xx_fw_version and can race routine driver unbind, rmmod, or PCI hot-remove. No separate victim action such as mounting a filesystem or confirming a prompt is required.
S:U - The use-after-free corrupts the host kernel heap object qla_chip_state_84xx within the same kernel security authority. It is not a VM escape, IOMMU/DMA isolation bypass, or sandbox breakout.
C:H - qla84xx_put_chip() kfree()s ha->cs84xx without clearing the pointer; a concurrent show() dereferences ha->cs84xx->op_fw_version. This kernel heap UAF lets a reused object be read, enabling arbitrary kernel information disclosure.
I:H - If the reused object's op_fw_version is zero, show() calls qla84xx_verify_chip(), which takes ha->cs84xx->access_lock and writes op_fw_version on the freed object. Heap spraying that UAF yields arbitrary write and control-flow hijack primitives.
A:H - Dereferencing the freed cs84xx pointer from sysfs context oopses or panics the kernel even when the UAF is not fully converted into a read/write primitive, so availability impact is complete.
| Attack Vector |
Local |
Scope |
Unchanged |
| Attack Complexity |
Low |
Confidentiality Impact |
High |
| Privileges Required |
Low |
Integrity Impact |
High |
| User Interaction |
None |
Availability Impact |
High |
AV:L - The UAF is reached from qla24xx_84xx_fw_version_show() on the SCSI host sysfs attribute while qla2x00_remove_one() tears down a QLogic ISP8432 (84xx) HBA. That is a local sysfs/PCI-unbind path, not a network or Fibre Channel frame handler.
AC:L - An attacker can loop-read /sys/class/scsi_host/hostN/84xx_fw_version while teardown runs. qla84xx_put_chip() freed cs84xx before scsi_remove_host(), leaving a large window through timer stop, DMA free, workqueue destroy, and fc_remove_host(). The attacker controls the sysfs side and can retry.
PR:L - 84xx_fw_version is DEVICE_ATTR(..., S_IRUGO) with no capable() check in qla24xx_84xx_fw_version_show(), so an unprivileged local user can read it. Per CNA driver-removal UAF precedent, concurrent PCI unbind or rmmod does not require the attacker to hold init-namespace root.
UI:N - The attacker performs their own sysfs reads against 84xx_fw_version and can race routine driver unbind, rmmod, or PCI hot-remove. No separate victim action such as mounting a filesystem or confirming a prompt is required.
S:U - The use-after-free corrupts the host kernel heap object qla_chip_state_84xx within the same kernel security authority. It is not a VM escape, IOMMU/DMA isolation bypass, or sandbox breakout.
C:H - qla84xx_put_chip() kfree()s ha->cs84xx without clearing the pointer; a concurrent show() dereferences ha->cs84xx->op_fw_version. This kernel heap UAF lets a reused object be read, enabling arbitrary kernel information disclosure.
I:H - If the reused object's op_fw_version is zero, show() calls qla84xx_verify_chip(), which takes ha->cs84xx->access_lock and writes op_fw_version on the freed object. Heap spraying that UAF yields arbitrary write and control-flow hijack primitives.
A:H - Dereferencing the freed cs84xx pointer from sysfs context oopses or panics the kernel even when the UAF is not fully converted into a read/write primitive, so availability impact is complete.
CVSS 3.1