CVE-2026-93186 is a vulnerability in Linux Kernel
Published on September 17, 2026
cxl/mbox: Clamp mailbox output allocation to the payload size
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.
Products Associated with CVE-2026-93186
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Affected Versions
Linux:- Version 583fa5e71caeb79e04e477e9837e2f7fa53b71e4 and below f5d2bbf0300f46307948864fbb97bce5097f4fe2 is affected.
- Version 583fa5e71caeb79e04e477e9837e2f7fa53b71e4 and below 31d4841eca7c4b75751ca96d24339e19303337f2 is affected.
- Version 583fa5e71caeb79e04e477e9837e2f7fa53b71e4 and below b4e11c731d6bee3b87315e055a1ca417c92dc1fc is affected.
- Version 583fa5e71caeb79e04e477e9837e2f7fa53b71e4 and below 8a13db9f899d149c3aab24abcb668121cfda5a4f is affected.
- Version 5.12 is affected.
- Before 5.12 is unaffected.
- Version 6.12.110, <= 6.12.* is unaffected.
- Version 6.18.52, <= 6.18.* is unaffected.
- Version 7.2.6, <= 7.2.* is unaffected.
- Version 7.3-rc1, <= * is unaffected.