{"id":"AZL-92778","summary":"CVE-2026-63960 affecting package kernel for versions less than 6.6.144.1-2","details":"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 \u003c USBC_RXINFO_RXBYTES(info); i++)\n\t\tregmap_read(wcove-\u003eregmap, 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.","modified":"2026-08-28T17:47:39.340490542Z","published":"2026-07-19T16:17:14Z","upstream":["CVE-2026-63960"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63960"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.144.1-2"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-92778.json"}}],"schema_version":"1.9.0"}