Bug 2546355 (CVE-2026-98232)

Summary: CVE-2026-98232 kernel: kernel: arbitrary code execution via out-of-bounds stack access in scsi_cdl_enable()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in the Linux kernel's SCSI subsystem. This vulnerability allows a malicious USB storage device to achieve arbitrary code execution or disclose sensitive kernel memory. By returning malformed MODE SENSE length values for a device advertising Command Duration Limits (CDL) support, an attacker can trigger an integer underflow and out-of-bounds stack memory access in the scsi_cdl_enable() function during automatic device scanning without requiring user interaction.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-10-06 09:04:49 UTC
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.