FKIE_CVE-2026-74655

Vulnerability from fkie_nvd - Published: 2026-08-22 16:16 - Updated: 2026-10-14 13:10
Severity
8.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Summary
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. 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.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1606abb7ce8c0cfef98c7e556b83c14e5d73c1bf
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1c31e2377f4c1bb110ca7f6e597b2253a7440c37
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/313ae287442e5e8d3f7b53b73f37d384bda072d0
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b1801c0d40f62778b613334de5840aba10a564d5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e3c04834ae1ab5e9cfbe8ac54ec734aa4774249d
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/tty/serial/qcom_geni_serial.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "1606abb7ce8c0cfef98c7e556b83c14e5d73c1bf",
              "status": "affected",
              "version": "2aaa43c7077833301c237684cd7bc9ae5e3dec95",
              "versionType": "git"
            },
            {
              "lessThan": "313ae287442e5e8d3f7b53b73f37d384bda072d0",
              "status": "affected",
              "version": "2aaa43c7077833301c237684cd7bc9ae5e3dec95",
              "versionType": "git"
            },
            {
              "lessThan": "1c31e2377f4c1bb110ca7f6e597b2253a7440c37",
              "status": "affected",
              "version": "2aaa43c7077833301c237684cd7bc9ae5e3dec95",
              "versionType": "git"
            },
            {
              "lessThan": "b1801c0d40f62778b613334de5840aba10a564d5",
              "status": "affected",
              "version": "2aaa43c7077833301c237684cd7bc9ae5e3dec95",
              "versionType": "git"
            },
            {
              "lessThan": "e3c04834ae1ab5e9cfbe8ac54ec734aa4774249d",
              "status": "affected",
              "version": "2aaa43c7077833301c237684cd7bc9ae5e3dec95",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/tty/serial/qcom_geni_serial.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.3"
            },
            {
              "lessThan": "6.3",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.154",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.104",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.45",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "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."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nserial: qcom-geni: corregir el vaciado del b\u00fafer DMA de TX\n\nAl vaciar la transmisi\u00f3n de una UART qcom-geni durante un DMA de TX en curso, la UART se queda atascada repitiendo infinitamente tramas DMA de TX corruptas.\n\nLas uart_ops en modo DMA no proporcionan una funci\u00f3n de devoluci\u00f3n de llamada flush_buffer, por lo que una transferencia en curso puede completarse despu\u00e9s de que el n\u00facleo serie haya reiniciado el kfifo de transmisi\u00f3n, causando un desbordamiento negativo de su longitud y reenviando transferencias de tama\u00f1o de p\u00e1gina indefinidamente. A\u00f1adir una que detenga la transferencia y borre tx_remaining y tx_queued.\n\nLa ruta de parada tambi\u00e9n estaba rota: desmapeaba el b\u00fafer mientras el motor serie a\u00fan pod\u00eda leerlo, y nunca reiniciaba la m\u00e1quina de estados del DMA de TX. Cancelar primero el comando principal del secuenciador, luego reiniciar la m\u00e1quina de estados y esperar a que termine antes de desmapear. Eliminar el retorno anticipado para que un mapeo pendiente tambi\u00e9n se limpie cuando el comando principal est\u00e9 inactivo.\n\nEl error puede ser provocado desde el espacio de usuario con una escritura grande inmediatamente seguida por TCOFLUSH. Un tcdrain posterior se colgar\u00e1 para siempre. El error fue reproducido y esta correcci\u00f3n fue validada en Arduino Uno Q (QRB2210) usando /dev/ttyHS1."
    }
  ],
  "id": "CVE-2026-74655",
  "lastModified": "2026-10-14T13:10:00.187",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.0,
        "impactScore": 6.0,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-22T16:16:39.067",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "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"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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