{"id":"CVE-2026-63960","state":"PUBLISHED","title":"usb: typec: wcove: don't write past struct pd_message in wcove_read_rx_buffer()","description":"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.","publishedAt":"2026-07-19T14:55:50.282Z","updatedAt":"2026-07-20T06:41:40.389Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"3c4fb9f169214290ec9a943907321e6265b36f65","status":"affected","lessThan":"3e632098d0521257ea965bbd6fde807d9bee5c8a","versionType":"git"},{"version":"3c4fb9f169214290ec9a943907321e6265b36f65","status":"affected","lessThan":"f2a1edc0bd142edabc6c85d88713f2bc178dd317","versionType":"git"},{"version":"3c4fb9f169214290ec9a943907321e6265b36f65","status":"affected","lessThan":"6899f5b6d7b83ce79a3d331dc61dd31bf73f9c22","versionType":"git"},{"version":"3c4fb9f169214290ec9a943907321e6265b36f65","status":"affected","lessThan":"5cd0e7ac4eefbdb330f8c72694fe74e63df65552","versionType":"git"},{"version":"3c4fb9f169214290ec9a943907321e6265b36f65","status":"affected","lessThan":"d0e4b8b3c6b7607a16932556eaaca5d5cf69f192","versionType":"git"},{"version":"3c4fb9f169214290ec9a943907321e6265b36f65","status":"affected","lessThan":"e94933dc41b87503bf585c8c6d53d740620eceb9","versionType":"git"},{"version":"3c4fb9f169214290ec9a943907321e6265b36f65","status":"affected","lessThan":"3f9d50c8b02b4af0646aa892465080f9061fc89c","versionType":"git"},{"version":"3c4fb9f169214290ec9a943907321e6265b36f65","status":"affected","lessThan":"4af7ad0e6d7aa4403dbb1dac7b9659b0421efcaa","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/usb/typec/tcpm/wcove.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.15","versionType":"semver"},{"version":"5.10.259","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.210","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.176","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.143","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.93","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.35","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.12","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/usb/typec/tcpm/wcove.c"]}],"references":["https://git.kernel.org/stable/c/3e632098d0521257ea965bbd6fde807d9bee5c8a","https://git.kernel.org/stable/c/f2a1edc0bd142edabc6c85d88713f2bc178dd317","https://git.kernel.org/stable/c/6899f5b6d7b83ce79a3d331dc61dd31bf73f9c22","https://git.kernel.org/stable/c/5cd0e7ac4eefbdb330f8c72694fe74e63df65552","https://git.kernel.org/stable/c/d0e4b8b3c6b7607a16932556eaaca5d5cf69f192","https://git.kernel.org/stable/c/e94933dc41b87503bf585c8c6d53d740620eceb9","https://git.kernel.org/stable/c/3f9d50c8b02b4af0646aa892465080f9061fc89c","https://git.kernel.org/stable/c/4af7ad0e6d7aa4403dbb1dac7b9659b0421efcaa"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/63xxx/CVE-2026-63960.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-63960","state":"PUBLISHED","datePublished":"2026-07-19T14:55:50.282Z","dateUpdated":"2026-07-20T06:41:40.389Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T07:54:57.023Z"},"containers":{"cna":{"title":"usb: typec: wcove: don't write past struct pd_message in wcove_read_rx_buffer()","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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"3c4fb9f169214290ec9a943907321e6265b36f65","status":"affected","lessThan":"3e632098d0521257ea965bbd6fde807d9bee5c8a","versionType":"git"},{"version":"3c4fb9f169214290ec9a943907321e6265b36f65","status":"affected","lessThan":"f2a1edc0bd142edabc6c85d88713f2bc178dd317","versionType":"git"},{"version":"3c4fb9f169214290ec9a943907321e6265b36f65","status":"affected","lessThan":"6899f5b6d7b83ce79a3d331dc61dd31bf73f9c22","versionType":"git"},{"version":"3c4fb9f169214290ec9a943907321e6265b36f65","status":"affected","lessThan":"5cd0e7ac4eefbdb330f8c72694fe74e63df65552","versionType":"git"},{"version":"3c4fb9f169214290ec9a943907321e6265b36f65","status":"affected","lessThan":"d0e4b8b3c6b7607a16932556eaaca5d5cf69f192","versionType":"git"},{"version":"3c4fb9f169214290ec9a943907321e6265b36f65","status":"affected","lessThan":"e94933dc41b87503bf585c8c6d53d740620eceb9","versionType":"git"},{"version":"3c4fb9f169214290ec9a943907321e6265b36f65","status":"affected","lessThan":"3f9d50c8b02b4af0646aa892465080f9061fc89c","versionType":"git"},{"version":"3c4fb9f169214290ec9a943907321e6265b36f65","status":"affected","lessThan":"4af7ad0e6d7aa4403dbb1dac7b9659b0421efcaa","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/usb/typec/tcpm/wcove.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.15","versionType":"semver"},{"version":"5.10.259","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.210","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.176","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.143","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.93","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.35","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.12","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/usb/typec/tcpm/wcove.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/3e632098d0521257ea965bbd6fde807d9bee5c8a"},{"url":"https://git.kernel.org/stable/c/f2a1edc0bd142edabc6c85d88713f2bc178dd317"},{"url":"https://git.kernel.org/stable/c/6899f5b6d7b83ce79a3d331dc61dd31bf73f9c22"},{"url":"https://git.kernel.org/stable/c/5cd0e7ac4eefbdb330f8c72694fe74e63df65552"},{"url":"https://git.kernel.org/stable/c/d0e4b8b3c6b7607a16932556eaaca5d5cf69f192"},{"url":"https://git.kernel.org/stable/c/e94933dc41b87503bf585c8c6d53d740620eceb9"},{"url":"https://git.kernel.org/stable/c/3f9d50c8b02b4af0646aa892465080f9061fc89c"},{"url":"https://git.kernel.org/stable/c/4af7ad0e6d7aa4403dbb1dac7b9659b0421efcaa"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-07-20T06:41:40.389Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.15","versionEndExcluding":"5.10.259"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.15","versionEndExcluding":"5.15.210"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.15","versionEndExcluding":"6.1.176"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.15","versionEndExcluding":"6.6.143"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.15","versionEndExcluding":"6.12.93"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.15","versionEndExcluding":"6.18.35"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.15","versionEndExcluding":"7.0.12"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.15","versionEndExcluding":"7.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}