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i3c: master: svc: bound IBI payload to the requested max_payload_len

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: i3c: master: svc: bound IBI payload to the requested max_payload_len svc_i3c_master_handle_ibi() reads the IBI payload from the RX FIFO into the IBI slot. The loop is bounded by the hardware FIFO size (SVC_I3C_FIFO_SIZE), not by the slot size. slot->data points into the IBI pool, which i3c_generic_ibi_alloc_pool() sizes at max_payload_len per slot. svc_i3c_master_request_ibi() only rejects a max_payload_len larger than SVC_I3C_FIFO_SIZE, so a driver can request a smaller one. mctp-i3c requests 1. Each readsb() then copies the controller RXCOUNT bytes (up to 31) with no check against the slot size. A device that sends more bytes than the slot holds writes past slot->data, an out-of-bounds write into the IBI pool. Bound the loop by dev->ibi->max_payload_len and clamp each read to the space left in the slot, the same way dw-i3c does. A device can still send more than the requested payload. Flush the leftover bytes from the RX FIFO so they do not leak into the next transfer.

Announced Source revision 1
Original source ↗

CVE-2026-80951

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-80951

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
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Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "dd3c52846d5954acd43f0e771689302f27dadc28",
        "lessThan": "7c099b0b292a68d0ef558527945dbfb756fbf893",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "dd3c52846d5954acd43f0e771689302f27dadc28",
        "lessThan": "7cc5ba756bc1cfffab9cb2695742f9f479dc73f7",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "dd3c52846d5954acd43f0e771689302f27dadc28",
        "lessThan": "35aa6730b8c5626b879a4e893fe664f59bf07d7f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "dd3c52846d5954acd43f0e771689302f27dadc28",
        "lessThan": "f296a0d5907bf88314dfda67245f7f69d1552470",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "dd3c52846d5954acd43f0e771689302f27dadc28",
        "lessThan": "5697d779577e2786ff3348ae9b77020ac0cf0aab",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "dd3c52846d5954acd43f0e771689302f27dadc28",
        "lessThan": "aac3c5aababc7fb69d5bf5b0cc52d308574e3a8c",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "dd3c52846d5954acd43f0e771689302f27dadc28",
        "lessThan": "e2bda39d7f9f285ec803e200b5c1f17143d0b483",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "drivers/i3c/master/svc-i3c-master.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.12"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.12",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.15.221",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.188",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.157",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.109",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.50",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.4",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "drivers/i3c/master/svc-i3c-master.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-80951

Source reference: /cveMetadata/cveId

Publisher severity

No explicit severity was provided.

Event
#34909 · Revision 1
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Publisher date
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