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.
Metrics
Affected Vendors & Products
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OpenCVE Enrichment is a feature of OpenCVE that uses AI to automatically link vendors and products to CVEs. Learn more on GitHub.
| Vendors | Products |
|---|---|
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Linux
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Linux Kernel
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| Source | ID | Title |
|---|---|---|
 Debian DLA |
DLA-4817-1 | linux-6.12 security update |
 Debian DSA |
DSA-6528-1 | linux security update |
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
Fri, 30 Oct 2026 12:45:00 +0000
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| References |
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Wed, 21 Oct 2026 13:15:00 +0000
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| References |
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Sat, 19 Sep 2026 08:45:00 +0000
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| Weaknesses | CWE-188 |
Thu, 17 Sep 2026 16:30:00 +0000
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| Description | 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. | |
| Title | cxl/mbox: Clamp mailbox output allocation to the payload size | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-10-30T12:36:18.449Z
Reserved: 2026-09-17T16:02:15.091Z
Link: CVE-2026-93186
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-17T17:18:14.683
Modified: 2026-10-30T13:20:59.543
Link: CVE-2026-93186
Redhat
No data.
OpenCVE Enrichment
Updated: 2026-09-19T21:30:16Z