CVE-2026-93093 (GCVE-0-2026-93093)
Vulnerability from cvelistv5
Published
2026-09-17 16:11
Modified
2026-10-21 12:51
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: firmware: arm_scmi: Publish channel state before callbacks Transport setup can enable callbacks before the setup routine returns. mailbox_chan_setup() registers the mailbox client with mbox_request_channel(), and the mailbox controller startup path can enable interrupt delivery before SCMI mailbox channel state has been published. Similarly, smc_chan_setup() requests the optional A2P completion IRQ before the SMC transport has made its cinfo pointer visible. If a pending or spurious callback fires in those windows, the transport RX callback can dereference a NULL transport cinfo pointer. Publishing only the transport-private pointer is not sufficient either: an early callback can enter the SCMI core before scmi_chan_setup() has assigned cinfo->handle. The core derives scmi_info from cinfo->handle in the RX path, so a NULL handle can still fault even when the transport-private cinfo is valid. Assign cinfo->handle before invoking the transport setup callback. Publish the mailbox and SMC transport-private channel state before requesting the mailbox channels or IRQ, and clear the early-published pointers again on setup failure. Also unwind mailbox setup devres resources on failure so an optional RX setup error that is ignored by the core does not leave stale transport state behind.
References
Impacted products
Vendor Product Version
Linux Linux Version: 5c8a47a5a91d4d6e185f758d61997613d9c5d6ac
Version: 5c8a47a5a91d4d6e185f758d61997613d9c5d6ac
Version: 5c8a47a5a91d4d6e185f758d61997613d9c5d6ac
Version: 5c8a47a5a91d4d6e185f758d61997613d9c5d6ac
Version: 5c8a47a5a91d4d6e185f758d61997613d9c5d6ac
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{
  "containers": {
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/firmware/arm_scmi/driver.c",
            "drivers/firmware/arm_scmi/transports/mailbox.c",
            "drivers/firmware/arm_scmi/transports/smc.c"
          ],
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          "programFiles": [
            "drivers/firmware/arm_scmi/driver.c",
            "drivers/firmware/arm_scmi/transports/mailbox.c",
            "drivers/firmware/arm_scmi/transports/smc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "version": "6.18.52",
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              "version": "7.2.6",
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              "version": "7.3",
              "versionType": "original_commit_for_fix"
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      ],
      "cpeApplicability": [
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              "cpeMatch": [
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfirmware: arm_scmi: Publish channel state before callbacks\n\nTransport setup can enable callbacks before the setup routine returns.\nmailbox_chan_setup() registers the mailbox client with\nmbox_request_channel(), and the mailbox controller startup path can enable\ninterrupt delivery before SCMI mailbox channel state has been published.\nSimilarly, smc_chan_setup() requests the optional A2P completion IRQ before\nthe SMC transport has made its cinfo pointer visible.\n\nIf a pending or spurious callback fires in those windows, the transport RX\ncallback can dereference a NULL transport cinfo pointer. Publishing only\nthe transport-private pointer is not sufficient either: an early callback\ncan enter the SCMI core before scmi_chan_setup() has assigned\ncinfo-\u003ehandle.\nThe core derives scmi_info from cinfo-\u003ehandle in the RX path, so a NULL\nhandle can still fault even when the transport-private cinfo is valid.\n\nAssign cinfo-\u003ehandle before invoking the transport setup callback. Publish\nthe mailbox and SMC transport-private channel state before requesting the\nmailbox channels or IRQ, and clear the early-published pointers again on\nsetup failure. Also unwind mailbox setup devres resources on failure so an\noptional RX setup error that is ignored by the core does not leave stale\ntransport state behind."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-21T12:51:52.039Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/50e38091a657ad81385e2aea7e2575e17ac23d79"
        },
        {
          "url": "https://git.kernel.org/stable/c/6f3f532531e4a27d28a2240719d1b05ac11766c6"
        },
        {
          "url": "https://git.kernel.org/stable/c/1bea027f7ef6fb889628b16c568a5f7c07a51b30"
        },
        {
          "url": "https://git.kernel.org/stable/c/a1bc587568a4e373db76261dc9561dfc3653917f"
        },
        {
          "url": "https://git.kernel.org/stable/c/0314900dcdde044af0208fed212035dbfaa55843"
        }
      ],
      "title": "firmware: arm_scmi: Publish channel state before callbacks",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-93093",
    "datePublished": "2026-09-17T16:11:08.360Z",
    "dateReserved": "2026-09-17T16:02:15.084Z",
    "dateUpdated": "2026-10-21T12:51:52.039Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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