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CVE-2026-72141 (GCVE-0-2026-72141)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:53 – Updated: 2026-08-17 05:40
VLAI
Title
i2c: imx: fix locked bus on SMBus block-read of 0 (IRQ)
Summary
In the Linux kernel, the following vulnerability has been resolved: i2c: imx: fix locked bus on SMBus block-read of 0 (IRQ) SMBus 3.1 6.5.7 allows a Block Read byte count of 0, but the interrupt-driven block-read state machine rejects it as -EPROTO. Worse, it returns without a NACK+STOP: the next receive cycle has already started, so the target keeps holding SDA and the bus stays stuck until a power cycle of this i2c controller. Accept count=0: NACK the in-flight dummy byte (TXAK) and set msg->len to 2 so i2c_imx_isr_read_continue() emits STOP via its normal last-byte path. The dummy byte is discarded; block-read callers only consume buf[0..count-1]. Reading I2DR has likewise already armed the next byte on the count > I2C_SMBUS_BLOCK_MAX error path, so NACK it (TXAK) before aborting with -EPROTO; otherwise the failing transfer's STOP cannot complete and the bus stays held. The atomic path regressed earlier (v3.16) and is fixed separately; this patch covers only the v6.13 state-machine rework.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 5f5c2d4579ca6836f5604cca979debd68ecfe23f , < 5d3240f42a667e29262aff76fdebfcdac4980626 (git)
Affected: 5f5c2d4579ca6836f5604cca979debd68ecfe23f , < 56ddfc18ea8f7d77747658892873eb632b2ed530 (git)
Affected: 5f5c2d4579ca6836f5604cca979debd68ecfe23f , < 07fd9385f0d87dff4b34f355f68adf701080cb24 (git)
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Linux Linux Affected: 6.13
Unaffected: 0 , < 6.13 (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/i2c/busses/i2c-imx.c"
          ],
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          "vendor": "Linux",
          "versions": [
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              "status": "affected",
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              "versionType": "git"
            },
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              "version": "5f5c2d4579ca6836f5604cca979debd68ecfe23f",
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          "vendor": "Linux",
          "versions": [
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              "version": "6.13"
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              "versionType": "original_commit_for_fix"
            }
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      "cpeApplicability": [
        {
          "nodes": [
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              "cpeMatch": [
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                  "versionStartIncluding": "6.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.13",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ni2c: imx: fix locked bus on SMBus block-read of 0 (IRQ)\n\nSMBus 3.1 6.5.7 allows a Block Read byte count of 0, but the\ninterrupt-driven block-read state machine rejects it as -EPROTO. Worse,\nit returns without a NACK+STOP: the next receive cycle has already\nstarted, so the target keeps holding SDA and the bus stays stuck until a\npower cycle of this i2c controller.\n\nAccept count=0: NACK the in-flight dummy byte (TXAK) and set msg-\u003elen to\n2 so i2c_imx_isr_read_continue() emits STOP via its normal last-byte\npath. The dummy byte is discarded; block-read callers only consume\nbuf[0..count-1].\n\nReading I2DR has likewise already armed the next byte on the\ncount \u003e I2C_SMBUS_BLOCK_MAX error path, so NACK it (TXAK) before aborting\nwith -EPROTO; otherwise the failing transfer\u0027s STOP cannot complete and\nthe bus stays held.\n\nThe atomic path regressed earlier (v3.16) and is fixed separately; this\npatch covers only the v6.13 state-machine rework."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - On NXP Layerscape/i.MX appliances, remotely reachable IPMI-over-LAN or management-plane requests invoke ipmi_ssif/pmbus i2c_smbus_read_block_data() on imx-i2c; a malicious or compromised bus peripheral returning SMBus block-read count 0 reaches the vulnerable IRQ handler without local login.\nAC:L - Once an SMBus block-read transaction is initiated and the target returns count byte 0 (a valid SMBus 3.1 response), the IRQ path deterministically omits NACK/STOP and locks the bus; the attacker controls both transaction initiation and slave response via compromised BMC/PMBus device or planted peripheral.\nPR:N - No Linux credentials are required when a malicious or compromised I2C slave returns count 0 during kernel-initiated SMBus block reads from IPMI SSIF, PMBus hwmon polling, or other automated drivers; OS privilege is not needed beyond influencing the bus response.\nUI:N - Exploitation requires no victim interaction because kernel subsystems (IPMI SSIF, PMBus hwmon, sensor drivers) automatically perform SMBus block reads during normal remote-management or background monitoring operations once the bus device responds.\nS:U - Impact is confined to locking the imx-i2c controller and attached I2C bus within the same kernel/host security boundary; it does not cross VM, container, or IOMMU isolation boundaries.\nC:N - The flaw is a missing NACK/STOP during SMBus block-read length handling; it causes a stuck I2C bus but does not corrupt kernel memory, leak data, or provide read primitives.\nI:N - No kernel or user data is modified; the bug only leaves the I2C controller in a hung bus state without write primitives, code execution, or integrity violations beyond loss of bus function.\nA:H - A successful trigger permanently locks the imx-i2c bus until controller power-cycle, denying all further I2C/SMBus communication to PMICs, sensors, EEPROMs, and BMC SSIF on safety-critical embedded, automotive, and datacenter systems."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:40:49.962Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/5d3240f42a667e29262aff76fdebfcdac4980626"
        },
        {
          "url": "https://git.kernel.org/stable/c/56ddfc18ea8f7d77747658892873eb632b2ed530"
        },
        {
          "url": "https://git.kernel.org/stable/c/07fd9385f0d87dff4b34f355f68adf701080cb24"
        }
      ],
      "title": "i2c: imx: fix locked bus on SMBus block-read of 0 (IRQ)",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-72141",
    "datePublished": "2026-08-15T05:53:14.754Z",
    "dateReserved": "2026-08-09T03:40:39.908Z",
    "dateUpdated": "2026-08-17T05:40:49.962Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-72141",
      "date": "2026-09-05",
      "epss": "0.00576",
      "percentile": "0.45127"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-72141\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-15T06:21:31.717\",\"lastModified\":\"2026-08-17T06:18:14.070\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\ni2c: imx: fix locked bus on SMBus block-read of 0 (IRQ)\\n\\nSMBus 3.1 6.5.7 allows a Block Read byte count of 0, but the\\ninterrupt-driven block-read state machine rejects it as -EPROTO. Worse,\\nit returns without a NACK+STOP: the next receive cycle has already\\nstarted, so the target keeps holding SDA and the bus stays stuck until a\\npower cycle of this i2c controller.\\n\\nAccept count=0: NACK the in-flight dummy byte (TXAK) and set msg-\u003elen to\\n2 so i2c_imx_isr_read_continue() emits STOP via its normal last-byte\\npath. The dummy byte is discarded; block-read callers only consume\\nbuf[0..count-1].\\n\\nReading I2DR has likewise already armed the next byte on the\\ncount \u003e I2C_SMBUS_BLOCK_MAX error path, so NACK it (TXAK) before aborting\\nwith -EPROTO; otherwise the failing transfer\u0027s STOP cannot complete and\\nthe bus stays held.\\n\\nThe atomic path regressed earlier (v3.16) and is fixed separately; this\\npatch covers only the v6.13 state-machine rework.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"drivers/i2c/busses/i2c-imx.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"5f5c2d4579ca6836f5604cca979debd68ecfe23f\",\"lessThan\":\"5d3240f42a667e29262aff76fdebfcdac4980626\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"5f5c2d4579ca6836f5604cca979debd68ecfe23f\",\"lessThan\":\"56ddfc18ea8f7d77747658892873eb632b2ed530\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"5f5c2d4579ca6836f5604cca979debd68ecfe23f\",\"lessThan\":\"07fd9385f0d87dff4b34f355f68adf701080cb24\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"drivers/i2c/busses/i2c-imx.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.13\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.13\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.40\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.5\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":7.5,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":3.6}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/07fd9385f0d87dff4b34f355f68adf701080cb24\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/56ddfc18ea8f7d77747658892873eb632b2ed530\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/5d3240f42a667e29262aff76fdebfcdac4980626\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2026-08-19T05:25:46+00:00",
      "cve": "CVE-2026-72141",
      "id": "CVE-2026-72141",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "76",
      "product_status:known_not_affected": "198",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: i2c: imx: fix locked bus on SMBus block-read of 0 (IRQ)",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72141.json",
      "version": "3"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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