CVE Catalog

CVE-2026-93093

Unknown
Published: Translated: NVD NIST

Summary

In the Linux kernel's ARM SCMI subsystem, a vulnerability exists where channel state is published after callbacks are enabled, potentially leading to NULL pointer dereference in the RX callback. This affects both mailbox and SMC channels, where early interrupts can trigger callbacks before the cinfo or handle pointers are initialized.

Risk Assessment

An attacker could exploit this vulnerability to cause a kernel panic or potentially escalate privileges if they can trigger a callback at an inappropriate time.

Recommendation

Apply the Linux kernel patch that publishes channel state before enabling callbacks and clears pointers on setup failure. Update your system to a kernel version containing this fix.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: firmware: arm_scmi: Publish channel state before callbacks Transport setup can enable callbacks before the setup routine returns. mailbox_chan_setup() registers the mailbox client with mbox_request_channel(), and the mailbox controller startup path can enable interrupt delivery before SCMI mailbox channel state has been published. Similarly, smc_chan_setup() requests the optional A2P completion IRQ before the SMC transport has made its cinfo pointer visible. If a pending or spurious callback fires in those windows, the transport RX callback can dereference a NULL transport cinfo pointer. Publishing only the transport-private pointer is not sufficient either: an early callback can enter the SCMI core before scmi_chan_setup() has assigned cinfo->handle. The core derives scmi_info from cinfo->handle in the RX path, so a NULL handle can still fault even when the transport-private cinfo is valid. Assign cinfo->handle before invoking the transport setup callback. Publish the mailbox and SMC transport-private channel state before requesting the mailbox channels or IRQ, and clear the early-published pointers again on setup failure. Also unwind mailbox setup devres resources on failure so an optional RX setup error that is ignored by the core does not leave stale transport state behind.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS