CVE-2026-93186: Linux

EPSS: 0.2% chance of exploitation in the next 30 days.

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.

Affected products

• Linux Linux: from 5.12, before 6.12.110 (fixed in 6.12.110); from 6.13, before 6.18.52 (fixed in 6.18.52); from 6.19, before 7.2.6 (fixed in 7.2.6)

Published 2026-09-17. Last modified 2026-09-17.