CVE-2026-93186

Full vulnerability record from the local CVENow database.

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.

Severity

Not scored

CVSS score

Not available

Vulnerability status

Received

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-09-17 17:18:14.683000

Last modified

2026-10-30 13:20:59.543000

View original CVE JSON

{
  "id": "CVE-2026-93186",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-09-17T17:18:14.683",
  "lastModified": "2026-10-30T13:20:59.543",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncxl/mbox: Clamp mailbox output allocation to the payload size\n\nCXL_MEM_SEND_COMMAND bounds the user's in.size to the mailbox payload\nsize but leaves out.size unbounded, then cxl_mbox_cmd_ctor() calls\nkvzalloc(out.size). A large out.size drives a huge allocation, above\nINT_MAX it WARNs and taints, and with panic_on_warn=1 it panics.\n\nThe transport __cxl_pci_mbox_send_cmd() already clamps the response copy\nto min(out.size, payload_size, device len), so the output buffer is\nnever written beyond payload_size. Clamp the allocation to payload_size\ntoo, matching the RAW path."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "drivers/cxl/core/mbox.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "583fa5e71caeb79e04e477e9837e2f7fa53b71e4",
              "lessThan": "123f6d154253939ce38f0ec0b6d1ba67f870e01f",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "583fa5e71caeb79e04e477e9837e2f7fa53b71e4",
              "lessThan": "d2d40574b9b272ade32d0d77b140d990e7547f5f",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "583fa5e71caeb79e04e477e9837e2f7fa53b71e4",
              "lessThan": "f5d2bbf0300f46307948864fbb97bce5097f4fe2",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "583fa5e71caeb79e04e477e9837e2f7fa53b71e4",
              "lessThan": "31d4841eca7c4b75751ca96d24339e19303337f2",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "583fa5e71caeb79e04e477e9837e2f7fa53b71e4",
              "lessThan": "b4e11c731d6bee3b87315e055a1ca417c92dc1fc",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "583fa5e71caeb79e04e477e9837e2f7fa53b71e4",
              "lessThan": "8a13db9f899d149c3aab24abcb668121cfda5a4f",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "drivers/cxl/core/mbox.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "5.12",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "5.12",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.1.191",
              "lessThanOrEqual": "6.1.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.6.160",
              "lessThanOrEqual": "6.6.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.12.110",
              "lessThanOrEqual": "6.12.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.52",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2.6",
              "lessThanOrEqual": "7.2.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.3",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/123f6d154253939ce38f0ec0b6d1ba67f870e01f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/31d4841eca7c4b75751ca96d24339e19303337f2",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/8a13db9f899d149c3aab24abcb668121cfda5a4f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/b4e11c731d6bee3b87315e055a1ca417c92dc1fc",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d2d40574b9b272ade32d0d77b140d990e7547f5f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f5d2bbf0300f46307948864fbb97bce5097f4fe2",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}