CVE-2026-98232: scsi: core: Validate MODE SENSE lengths in scsi_cdl_enable()
In the Linux kernel, the following vulnerability has been resolved:
scsi: core: Validate MODE SENSE lengths in scsicdlenable()
scsicdlenable() 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 bufdata can point beyond buf.
During automatic scan, enable is false, so the read-modify-write of bufdata[4] can clear the low two bits of a target-selected out-of-bounds stack byte. scsimodeselect() 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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 6.6.158.1-1 - Upgrade
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debian/linuxto a version that resolves this vulnerability.Fixed in 6.1.176-1Fixed in 6.1.190-1Fixed in 6.12.115-2Fixed in 7.2.12-1Fixed in 7.2.15-1 - Upgrade
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debian/linux-6.12to a version that resolves this vulnerability.Fixed in 6.12.113-1~deb12u1 - Upgrade
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ubuntu/linux-hwe-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42~24.04.1 - Upgrade
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ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1~24.04.1 - Upgrade
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-42.42 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1016.17 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1016.18 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1015.16 - Upgrade
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ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1 - Compensating control
In scsi_cdl_enable(), validate and consume the MODE SENSE mode header and block descriptor lengths before locating the ATA feature mode page, cap the available length to the 64-byte buffer, and require the five bytes needed to access the CDL field.
Event History
Frequently Asked Questions
Which systems are exposed during device discovery?
Linux systems are exposed when they scan a USB storage device that identifies as an ATA device and advertises CDL support. The vulnerable path is reachable during automatic scanning.
Does exploitation require mounting the device or accessing its block device from userspace?
No. The issue can be reached without mounting a filesystem and without userspace access to the block device.
What can a malicious target cause if it reports malformed MODE SENSE lengths?
It can cause the kernel to use data beyond a 64-byte stack buffer when preparing a MODE SELECT request. Up to 64 bytes from outside that buffer may be copied into the outgoing payload, disclosing stack contents to the target.