CVE-2025-40118 scsi: pm80xx: Fix array-index-out-of-of-bounds on rmmod
A local attacker with root privileges can trigger a kernel crash by removing the pm80xx driver when an expander is connected.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-40118?
CVE-2025-40118 is a high-severity vulnerability in Linux, published on 12 Nov 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Which versions are affected by CVE-2025-40118?
How do I fix CVE-2025-40118?
Apply the vendor's patch.
Is CVE-2025-40118 being exploited?
There is no known exploitation of CVE-2025-40118 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2025-40118, DEBIAN-CVE-2025-40118, GHSA-fwp3-pc57-cmgf, ROOT-OS-DEBIAN-11-CVE-2025-40118, ROOT-OS-DEBIAN-13-CVE-2025-40118, UBUNTU-CVE-2025-40118.