CVE-2026-10644

Full vulnerability record from the local CVENow database.

Description

The Microchip SERCOM-G1 UART driver (drivers/serial/uart_mchp_sercom_g1.c), used by the PIC32CM-JH SoC family, contains an out-of-bounds write in its asynchronous (DMA) receive path. When uart_rx_enable() is invoked with a one-byte receive buffer (len == 1) and CONFIG_UART_MCHP_ASYNC is enabled, the RX-complete ISR starts a single-beat DMA transfer while a received byte is already pending in the SERCOM DATA register. On this SoC the peripheral-triggered DMA start sequencing then writes one byte past the end of the caller-supplied buffer (CWE-787). The overflowed byte's value is the UART RX data supplied by the connected serial peer (adjacent attacker), while its size and location are fixed at one byte immediately after the buffer. Exploitation requires the async UART config (not enabled by default on the in-tree PIC32CM-JH boards) and a consumer that enables RX with a one-byte buffer; impact is limited single-byte memory corruption adjacent to the RX buffer (possible crash / denial of service). The defect shipped in v4.4.0. The fix reads the first byte with the CPU and, for one-byte buffers, performs no DMA at all; for larger buffers it sizes the DMA for the remaining len-1 bytes.

Severity

LOW

CVSS score

3.1 (v3.1)

Vulnerability status

Modified

Source identifier

[email protected]

Published

2026-06-28 05:16:20.980000

Last modified

2026-10-25 17:10:00.197000

View original CVE JSON

{
  "id": "CVE-2026-10644",
  "sourceIdentifier": "[email protected]",
  "published": "2026-06-28T05:16:20.980",
  "lastModified": "2026-10-25T17:10:00.197",
  "vulnStatus": "Modified",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "The Microchip SERCOM-G1 UART driver (drivers/serial/uart_mchp_sercom_g1.c), used by the PIC32CM-JH SoC family, contains an out-of-bounds write in its asynchronous (DMA) receive path. When uart_rx_enable() is invoked with a one-byte receive buffer (len == 1) and CONFIG_UART_MCHP_ASYNC is enabled, the RX-complete ISR starts a single-beat DMA transfer while a received byte is already pending in the SERCOM DATA register. On this SoC the peripheral-triggered DMA start sequencing then writes one byte past the end of the caller-supplied buffer (CWE-787).\n\nThe overflowed byte's value is the UART RX data supplied by the connected serial peer (adjacent attacker), while its size and location are fixed at one byte immediately after the buffer.\n\nExploitation requires the async UART config (not enabled by default on the in-tree PIC32CM-JH boards) and a consumer that enables RX with a one-byte buffer; impact is limited single-byte memory corruption adjacent to the RX buffer (possible crash / denial of service).\n\nThe defect shipped in v4.4.0. The fix reads the first byte with the CPU and, for one-byte buffers, performs no DMA at all; for larger buffers it sizes the DMA for the remaining len-1 bytes."
    },
    {
      "lang": "es",
      "value": "El controlador UART Microchip SERCOM-G1 (drivers/serial/uart_mchp_sercom_g1.c), utilizado por la familia de SoC PIC32CM-JH, contiene una escritura fuera de límites en su ruta de recepción asíncrona (DMA). Cuando se invoca uart_rx_enable() con un búfer de recepción de un byte (len == 1) y CONFIG_UART_MCHP_ASYNC está habilitado, la ISR de RX-completo inicia una transferencia DMA de un solo ciclo mientras un byte recibido ya está pendiente en el registro SERCOM DATA. En este SoC, la secuencia de inicio de DMA activada por periférico luego escribe un byte más allá del final del búfer proporcionado por el llamador (CWE-787). El valor del byte desbordado son los datos UART RX suministrados por el par serie conectado (atacante adyacente), mientras que su tamaño y ubicación están fijados en un byte inmediatamente después del búfer. La explotación requiere la configuración UART asíncrona (no habilitada por defecto en las placas PIC32CM-JH del árbol) y un consumidor que habilite la recepción (RX) con un búfer de un byte; el impacto es una corrupción de memoria de un solo byte limitada adyacente al búfer RX (posible caída / denegación de servicio). El defecto se envió en la v4.4.0. La solución lee el primer byte con la CPU y, para búferes de un byte, no realiza ninguna DMA en absoluto; para búferes más grandes, dimensiona la DMA para los len-1 bytes restantes."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "zephyrproject",
          "product": "zephyr",
          "defaultStatus": "unaffected",
          "collectionURL": "https://github.com/zephyrproject-rtos/zephyr",
          "packageName": "zephyr",
          "programFiles": [
            "drivers/serial/uart_mchp_sercom_g1.c"
          ],
          "versions": [
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              "version": "4.4.0",
              "lessThan": "4.4.2",
              "versionType": "semver",
              "status": "affected"
            }
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        }
      ]
    }
  ],
  "metrics": {
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        "type": "Secondary",
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          "baseScore": 4.2,
          "baseSeverity": "MEDIUM",
          "attackVector": "ADJACENT_NETWORK",
          "attackComplexity": "HIGH",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "LOW",
          "availabilityImpact": "LOW"
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        "type": "Primary",
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          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
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    "ssvcV203": [
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          "id": "CVE-2026-10644",
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          "role": "CISA Coordinator",
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  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
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          "lang": "en",
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  ],
  "configurations": [
    {
      "nodes": [
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          "negate": false,
          "cpeMatch": [
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              "criteria": "cpe:2.3:o:zephyrproject:zephyr:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "4.4.0",
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              "matchCriteriaId": "BF44F4FC-9EF2-4562-ACEB-2BE5AE165E9C"
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  "references": [
    {
      "url": "https://github.com/zephyrproject-rtos/zephyr/commit/5251d2bc0070be801769fb7ce7b9066fef5d9f81",
      "source": "[email protected]",
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}