CVE Catalog

CVE-2026-93186

Unknown
Published: Translated: NVD NIST

Summary

In the Linux kernel, the cxl/mbox CXL_MEM_SEND_COMMAND bounds the user's in.size to the mailbox payload size but leaves out.size unbounded, which is then used in kvzalloc(). A large out.size drives a huge allocation, above INT_MAX it warns and taints the kernel, and with panic_on_warn=1 it panics.

Risk Assessment

A local user can trigger excessive memory allocation, a kernel warning, taint, or a system panic, causing a denial of service. It requires access to the CXL interface.

Recommendation

Update the Linux kernel to a version containing the fix that clamps the output allocation to the payload size. Restrict access to CXL devices to trusted users.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: cxl/mbox: Clamp mailbox output allocation to the payload size CXL_MEM_SEND_COMMAND bounds the user's in.size to the mailbox payload size but leaves out.size unbounded, then cxl_mbox_cmd_ctor() calls kvzalloc(out.size). A large out.size drives a huge allocation, above INT_MAX it WARNs and taints, and with panic_on_warn=1 it panics. The transport __cxl_pci_mbox_send_cmd() already clamps the response copy to min(out.size, payload_size, device len), so the output buffer is never written beyond payload_size. Clamp the allocation to payload_size too, matching the RAW path.

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