Bug 2464407 (CVE-2026-43007)

Summary: CVE-2026-43007 kernel: accel/qaic: Handle DBC deactivation if the owner went away
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the accel/qaic component of the Linux kernel. When a user process terminates before the device's deactivation transaction for a Device-Bound Context (DBC) is fully processed, the host system can become out of sync with available DBCs. This can lead to a denial of service, where a subsequent user attempting to activate a network may experience their process hanging indefinitely if assigned the same DBC.
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Description OSIDB Bzimport 2026-05-01 15:05:06 UTC 
In the Linux kernel, the following vulnerability has been resolved:

accel/qaic: Handle DBC deactivation if the owner went away

When a DBC is released, the device sends a QAIC_TRANS_DEACTIVATE_FROM_DEV
transaction to the host over the QAIC_CONTROL MHI channel. QAIC handles
this by calling decode_deactivate() to release the resources allocated for
that DBC. Since that handling is done in the qaic_manage_ioctl() context,
if the user goes away before receiving and handling the deactivation, the
host will be out-of-sync with the DBCs available for use, and the DBC
resources will not be freed unless the device is removed. If another user
loads and requests to activate a network, then the device assigns the same
DBC to that network, QAIC will "indefinitely" wait for dbc->in_use = false,
leading the user process to hang.

As a solution to this, handle QAIC_TRANS_DEACTIVATE_FROM_DEV transactions
that are received after the user has gone away.
Comment 1 Keith Grant 2026-05-01 16:05:08 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026050154-CVE-2026-43007-469f@gregkh/T