Riskcovery

CVE-2026-93186

cxl/mbox: Clamp mailbox output allocation to the payload size

State
Published
Severity
Not scored
Published
Sep 17, 2026
Updated
Oct 30, 2026
Reserved
Sep 17, 2026

Read the record on cve.org

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.

Scores

The record has no CVSS score.

Weaknesses

The record names no weakness.

Affected Products

ProductVersions
LinuxLinux
  • 583fa5e71caeb79e04e477e9837e2f7fa53b71e4 to before 123f6d154253939ce38f0ec0b6d1ba67f870e01fAffected
  • 583fa5e71caeb79e04e477e9837e2f7fa53b71e4 to before d2d40574b9b272ade32d0d77b140d990e7547f5fAffected
  • 583fa5e71caeb79e04e477e9837e2f7fa53b71e4 to before f5d2bbf0300f46307948864fbb97bce5097f4fe2Affected
  • 583fa5e71caeb79e04e477e9837e2f7fa53b71e4 to before 31d4841eca7c4b75751ca96d24339e19303337f2Affected
  • 583fa5e71caeb79e04e477e9837e2f7fa53b71e4 to before b4e11c731d6bee3b87315e055a1ca417c92dc1fcAffected
  • 583fa5e71caeb79e04e477e9837e2f7fa53b71e4 to before 8a13db9f899d149c3aab24abcb668121cfda5a4fAffected
LinuxLinux
  • 5.12Affected
  • before 5.12Not affected
  • 6.1.191 through 6.1.*Not affected
  • 6.6.160 through 6.6.*Not affected
  • 6.12.110 through 6.12.*Not affected
  • 6.18.52 through 6.18.*Not affected
  • 7.2.6 through 7.2.*Not affected
  • 7.3 and laterNot affected

References

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