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CVE-2026-74655

Estado: RecibidaAlta (8.8)—

In the Linux kernel, the following vulnerability has been resolved:

serial: qcom-geni: fix TX DMA buffer flush

When transmit flushing a qcom-geni UART during an ongoing TX DMA, the UART gets stuck infinitely repeating corrupted TX DMA frames.

The DMA-mode uart_ops does not provide a flush_buffer callback, so an in-flight transfer can complete after serial core has reset the transmit kfifo, underflowing its length and resubmitting page-sized transfers indefinitely. Add one that stops the transfer and clears tx_remaining and tx_queued.

The stop path was also broken: it unmapped the buffer while the serial engine could still read it, and never reset the TX DMA state machine.

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Cancel the main sequencer command first, then reset the state machine and wait for it before unmapping. Drop the early return so a pending mapping is also cleaned up when the main command is inactive.

The bug can be triggered from userspace with a large write immediately followed by TCOFLUSH. A following tcdrain will hang forever. The bug was reproduced and this fix was validated on Arduino Uno Q (QRB2210) using /dev/ttyHS1.

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

Vulnerabilidad local (AV:L/PR:L) sin interacción en kernel Linux causa corrupción de estado UART y bloqueo indefinido (DoS). Un atacante con privilegios locales puede desencadenarla para deshabilitar dispositivos de comunicación serial.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Threat Intelligence ProgramFilter Network TrafficExecution PreventionApplication Isolation and SandboxingExploit ProtectionUpdate Software

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux KernelAI

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-74655",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "CHANGED",
          "version": "3.1",
          "baseScore": 8.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 6,
        "exploitabilityScore": 2
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2aaa43c7077833301c237684cd7bc9ae5e3dec95",
              "lessThan": "1606abb7ce8c0cfef98c7e556b83c14e5d73c1bf",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "2aaa43c7077833301c237684cd7bc9ae5e3dec95",
              "lessThan": "313ae287442e5e8d3f7b53b73f37d384bda072d0",
              "versionType": "git"
            },
            {
              "status": "affected",
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              "lessThan": "1c31e2377f4c1bb110ca7f6e597b2253a7440c37",
              "versionType": "git"
            },
            {
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            {
              "status": "affected",
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              "lessThan": "e3c04834ae1ab5e9cfbe8ac54ec734aa4774249d",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "drivers/tty/serial/qcom_geni_serial.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.3"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.3",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.6.154",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.104",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.45",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "drivers/tty/serial/qcom_geni_serial.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-22T16:16:39.067",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/1606abb7ce8c0cfef98c7e556b83c14e5d73c1bf",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/1c31e2377f4c1bb110ca7f6e597b2253a7440c37",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/313ae287442e5e8d3f7b53b73f37d384bda072d0",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/b1801c0d40f62778b613334de5840aba10a564d5",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e3c04834ae1ab5e9cfbe8ac54ec734aa4774249d",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nserial: qcom-geni: fix TX DMA buffer flush\n\nWhen transmit flushing a qcom-geni UART during an ongoing TX DMA, the\nUART gets stuck infinitely repeating corrupted TX DMA frames.\n\nThe DMA-mode uart_ops does not provide a flush_buffer callback, so an\nin-flight transfer can complete after serial core has reset the transmit\nkfifo, underflowing its length and resubmitting page-sized transfers\nindefinitely. Add one that stops the transfer and clears tx_remaining\nand tx_queued.\n\nThe stop path was also broken: it unmapped the buffer while the serial\nengine could still read it, and never reset the TX DMA state machine.\nCancel the main sequencer command first, then reset the state machine\nand wait for it before unmapping. Drop the early return so a pending\nmapping is also cleaned up when the main command is inactive.\n\nThe bug can be triggered from userspace with a large write immediately\nfollowed by TCOFLUSH. A following tcdrain will hang forever. The bug was\nreproduced and this fix was validated on Arduino Uno Q (QRB2210)\nusing /dev/ttyHS1."
    }
  ],
  "lastModified": "2026-08-27T13:18:35.997",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}