CVE-2026-98232 scsi: core: Validate MODE SENSE lengths in scsi_cdl_enable()
A malicious USB storage device can trigger an out-of-bounds read in the Linux kernel SCSI subsystem, potentially disclosing stack memory or executing code during automatic device enumeration.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98232?
CVE-2026-98232 is a memory corruption vulnerability in Linux, published on 6 Oct 2026. 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: core: Validate MODE SENSE lengths in scsi_cdl_enable()
scsi_cdl_enable() uses length fields returned by MODE SENSE to locate the ATA feature mode page in a 64-byte stack buffer. A target can report a total length shorter than its mode header and block descriptors. The unsigned subtraction used for the MODE SELECT length can wrap, and the separately computed buf_data can point beyond buf.
During automatic scan, enable is false, so the read-modify-write of buf_data[4] can clear the low two bits of a target-selected out-of-bounds stack byte. scsi_mode_select() can then copy up to 64 bytes from outside the buffer into the outgoing MODE SELECT payload, disclosing stack contents to the target.
This is reachable while scanning a USB storage device that identifies as an ATA device and advertises CDL support. No filesystem mount or userspace access to the block device is required.
On upstream commit cee9395acd80 ("Linux 7.3-rc1"), a build-specific, one-vCPU QEMU/Raw Gadget proof using QEMU-only multi-UDC allocator sampling executed a fixed proof command inside the guest and created a UID-0-owned marker during automatic enumeration, with KASLR and NX enabled.
The issue was independently found during security research at Drivesec S.r.l.
Cap the available length to the buffer size. Validate and consume the mode header and block descriptor lengths before using the page, and require the five bytes needed to access the CDL field.
Which versions are affected by CVE-2026-98232?
How do I fix CVE-2026-98232?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-98232 being exploited?
There is no known exploitation of CVE-2026-98232 in the wild and no public exploit code.
Sources
Also known as AZL-105981, BELL-CVE-2026-98232, DEBIAN-CVE-2026-98232, GHSA-32q6-xj2g-42pm, UBUNTU-CVE-2026-98232.