CVE-2025-40118
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-11-12

Last updated on: 2025-11-12

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: scsi: pm80xx: Fix array-index-out-of-of-bounds on rmmod Since commit f7b705c238d1 ("scsi: pm80xx: Set phy_attached to zero when device is gone") UBSAN reports: UBSAN: array-index-out-of-bounds in drivers/scsi/pm8001/pm8001_sas.c:786:17 index 28 is out of range for type 'pm8001_phy [16]' on rmmod when using an expander. For a direct attached device, attached_phy contains the local phy id. For a device behind an expander, attached_phy contains the remote phy id, not the local phy id. I.e. while pm8001_ha will have pm8001_ha->chip->n_phy local phys, for a device behind an expander, attached_phy can be much larger than pm8001_ha->chip->n_phy (depending on the amount of phys of the expander). E.g. on my system pm8001_ha has 8 phys with phy ids 0-7. One of the ports has an expander connected. The expander has 31 phys with phy ids 0-30. The pm8001_ha->phy array only contains the phys of the HBA. It does not contain the phys of the expander. Thus, it is wrong to use attached_phy to index the pm8001_ha->phy array for a device behind an expander. Thus, we can only clear phy_attached for devices that are directly attached.
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Meta Information
Published
2025-11-12
Last Modified
2025-11-12
Generated
2026-05-07
AI Q&A
2025-11-13
EPSS Evaluated
2026-05-05
NVD
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *
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Exploitability
CWE
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CWE ID Description
CWE-UNKNOWN
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AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability is an array-index-out-of-bounds error in the Linux kernel's SCSI pm80xx driver. It occurs when removing the module (rmmod) while using an expander device. The issue arises because the code incorrectly uses a remote phy ID (which can be larger) to index an array that only contains local phys, leading to out-of-bounds access. This happens because the pm8001_ha->phy array only contains phys of the Host Bus Adapter (HBA), not the expander's phys. The fix ensures that phy_attached is only cleared for directly attached devices, preventing invalid array indexing.


How can this vulnerability impact me? :

This vulnerability can cause undefined behavior such as kernel crashes or memory corruption due to out-of-bounds array access when removing the pm80xx driver module with an expander device connected. This can lead to system instability or denial of service.


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