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CVE-2026-63960

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: usb: typec: wcove: don't write past struct pd_message in wcove_read_rx_buffer() wcove_read_rx_buffer() copies the PD RX FIFO into the caller's struct pd_message with for (i = 0; i < USBC_RXINFO_RXBYTES(info); i++) regmap_read(wcove->regmap, USBC_RX_DATA + i, msg + i); which has two problems: USBC_RXINFO_RXBYTES() is a 5-bit field (max 31) while struct pd_message is 30 bytes (__le16 header + __le32 payload[PD_MAX_PAYLOAD], packed). The byte count latched in RXINFO is the number of bytes the port partner put on the wire, so a malicious partner that transmits a 31-byte frame can drive the loop one byte past the destination if the WCOVE BMC receiver does not enforce the PD object-count limit in hardware. The existing FIXME flagged this as unverified. Independently, regmap_read() takes an unsigned int * and stores a full unsigned int at the destination. Passing the byte pointer msg + i means each iteration writes four bytes; the high three are zero (val_bits is 8) and are normally overwritten by the next iteration, but the final iteration's high bytes are not. With RXBYTES == 30 the i == 29 iteration already writes three zero bytes past msg, which sits on the IRQ thread's stack in wcove_typec_irq(). Clamp the loop to sizeof(struct pd_message) and read each register into a local before storing only its low byte, so the copy can never exceed the destination regardless of what RXINFO reports.

Severity
MEDIUM
CVSS score
5.5 (v3.1)
Vulnerability status
Analyzed
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-07-19 16:17:14.897000
Last modified
2026-10-30 14:31:22.270000
View original CVE JSON 
{
  "id": "CVE-2026-63960",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-07-19T16:17:14.897",
  "lastModified": "2026-10-30T14:31:22.270",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: typec: wcove: don't write past struct pd_message in wcove_read_rx_buffer()\n\nwcove_read_rx_buffer() copies the PD RX FIFO into the caller's\nstruct pd_message with\n\n\tfor (i = 0; i < USBC_RXINFO_RXBYTES(info); i++)\n\t\tregmap_read(wcove->regmap, USBC_RX_DATA + i, msg + i);\n\nwhich has two problems:\n\nUSBC_RXINFO_RXBYTES() is a 5-bit field (max 31) while struct pd_message\nis 30 bytes (__le16 header + __le32 payload[PD_MAX_PAYLOAD], packed).\nThe byte count latched in RXINFO is the number of bytes the port partner\nput on the wire, so a malicious partner that transmits a 31-byte frame\ncan drive the loop one byte past the destination if the WCOVE BMC\nreceiver does not enforce the PD object-count limit in hardware. The\nexisting FIXME flagged this as unverified.\n\nIndependently, regmap_read() takes an unsigned int * and stores a full\nunsigned int at the destination. Passing the byte pointer msg + i means\neach iteration writes four bytes; the high three are zero (val_bits is\n8) and are normally overwritten by the next iteration, but the final\niteration's high bytes are not. With RXBYTES == 30 the i == 29 iteration\nalready writes three zero bytes past msg, which sits on the IRQ thread's\nstack in wcove_typec_irq().\n\nClamp the loop to sizeof(struct pd_message) and read each register into\na local before storing only its low byte, so the copy can never exceed\nthe destination regardless of what RXINFO reports."
    }
  ],
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  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Primary",
        "cvssData": {
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          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
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        "exploitabilityScore": 1.8,
        "impactScore": 3.6
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  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Primary",
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
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  "configurations": [
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