{"id":"CVE-2026-19571","state":"PUBLISHED","title":"Race condition in ITE IT8xxx2 SHI host-command backend lets a second SPI request write an unvalidated length into the in-flight request buffer","description":"The ITE IT8xxx2 SHI host-command backend (subsys/mgmt/ec_host_cmd/backends/ec_host_cmd_backend_shi_ite.c) copied the 8-byte host-command request header from the SPI Rx FIFO directly into the shared receive buffer data->in_msg and only afterwards checked the protocol version and the derived packet length. The interrupt handler also accepted a chip-select assertion and an Rx-valid-length (RVLI) interrupt in any driver state other than SHI_STATE_DISABLED, so a new header could be parsed while the host-command thread was still processing the previous request out of the very same buffer.\n\nThe host processor is the SPI controller and drives both chip select and the clock. After sending a well-formed request it can immediately de-assert chip select — which returns the driver to the ready state and re-enables the FIFO — and start a second transaction carrying a header with data_len = 0xFFFF. Those eight bytes are written into in_msg before the oversized length is rejected, so they land in a buffer whose contents verify_rx() in subsys/mgmt/ec_host_cmd/ec_host_cmd_handler.c has already validated. If this lands in the window before the host-command thread executes args.input_buf_size = rx_header->data_len, the framework hands the registered command handler a 65535-byte input length over a 256-byte buffer.\n\nThe result is an out-of-bounds read of up to roughly 64 KiB beyond the request buffer: command handlers that copy or echo input_buf_size bytes disclose adjacent embedded-controller memory back to the host or overflow the response buffer, and a read past the end of SRAM faults the controller. The same race also allows cmd_id and cmd_ver to be swapped after checksum verification and after handler lookup. Exploitation requires the ability to drive the inter-processor SHI bus (a compromised host OS or physical access to the SPI lines) and winning a timing race, which the SPI controller can retry indefinitely.\n\nThe fix parses the header into a local struct ec_host_cmd_request_header and copies it into in_msg only after the length has been bounded by sizeof(data->in_msg), and ignores chip-select and RVLI interrupts outside SHI_STATE_READY_TO_RECV/SHI_STATE_RECEIVING. A residual, bounded race remains: an end-of-transaction interrupt still resets the state to ready while the host-command thread owns the buffer, so a valid second request can still overwrite the in-flight request's contents, unlike the NPCX backend which parks in SHI_STATE_CNL_RESP_NOT_RDY while the buffer is in use.","publishedAt":"2026-10-09T07:16:40.717Z","updatedAt":"2026-10-09T17:57:42.905Z","severity":{"score":6.7,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H","source":"zephyr"},"assigner":"zephyr","products":["zephyrproject zephyr"],"affected":[{"vendor":"zephyrproject","product":"zephyr","packageName":"zephyr","defaultStatus":"unaffected","versions":[{"version":"3.3.0","status":"affected","lessThan":"4.5.0","versionType":"semver"}],"collectionURL":"https://github.com/zephyrproject-rtos/zephyr","programFiles":["subsys/mgmt/ec_host_cmd/backends/ec_host_cmd_backend_shi_ite.c"],"programRoutines":[{"name":"shi_ite_cs_callback"},{"name":"shi_ite_int_handler"},{"name":"shi_ite_parse_header"}]}],"references":["https://github.com/zephyrproject-rtos/zephyr/commit/0636e65c825e810ad97f154606365870152d402f","https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-4x98-6536-cwjv"],"weaknesses":["CWE-362"],"ingestedAt":"2026-10-29T20:11:10.572Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/19xxx/CVE-2026-19571.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-19571","state":"PUBLISHED","datePublished":"2026-10-09T07:16:40.717Z","dateUpdated":"2026-10-09T17:57:42.905Z","assignerShortName":"zephyr","assignerOrgId":"e2e69745-5e70-4e92-8431-deb5529a81ad","dateReserved":"2026-08-11T19:15:07.946Z"},"containers":{"cna":{"title":"Race condition in ITE IT8xxx2 SHI host-command backend lets a second SPI request write an unvalidated length into the in-flight request buffer","descriptions":[{"lang":"en","value":"The ITE IT8xxx2 SHI host-command backend (subsys/mgmt/ec_host_cmd/backends/ec_host_cmd_backend_shi_ite.c) copied the 8-byte host-command request header from the SPI Rx FIFO directly into the shared receive buffer data->in_msg and only afterwards checked the protocol version and the derived packet length. The interrupt handler also accepted a chip-select assertion and an Rx-valid-length (RVLI) interrupt in any driver state other than SHI_STATE_DISABLED, so a new header could be parsed while the host-command thread was still processing the previous request out of the very same buffer.\n\nThe host processor is the SPI controller and drives both chip select and the clock. After sending a well-formed request it can immediately de-assert chip select — which returns the driver to the ready state and re-enables the FIFO — and start a second transaction carrying a header with data_len = 0xFFFF. Those eight bytes are written into in_msg before the oversized length is rejected, so they land in a buffer whose contents verify_rx() in subsys/mgmt/ec_host_cmd/ec_host_cmd_handler.c has already validated. If this lands in the window before the host-command thread executes args.input_buf_size = rx_header->data_len, the framework hands the registered command handler a 65535-byte input length over a 256-byte buffer.\n\nThe result is an out-of-bounds read of up to roughly 64 KiB beyond the request buffer: command handlers that copy or echo input_buf_size bytes disclose adjacent embedded-controller memory back to the host or overflow the response buffer, and a read past the end of SRAM faults the controller. The same race also allows cmd_id and cmd_ver to be swapped after checksum verification and after handler lookup. Exploitation requires the ability to drive the inter-processor SHI bus (a compromised host OS or physical access to the SPI lines) and winning a timing race, which the SPI controller can retry indefinitely.\n\nThe fix parses the header into a local struct ec_host_cmd_request_header and copies it into in_msg only after the length has been bounded by sizeof(data->in_msg), and ignores chip-select and RVLI interrupts outside SHI_STATE_READY_TO_RECV/SHI_STATE_RECEIVING. A residual, bounded race remains: an end-of-transaction interrupt still resets the state to ready while the host-command thread owns the buffer, so a valid second request can still overwrite the in-flight request's contents, unlike the NPCX backend which parks in SHI_STATE_CNL_RESP_NOT_RDY while the buffer is in use."}],"affected":[{"vendor":"zephyrproject","product":"zephyr","packageName":"zephyr","defaultStatus":"unaffected","versions":[{"version":"3.3.0","status":"affected","lessThan":"4.5.0","versionType":"semver"}],"collectionURL":"https://github.com/zephyrproject-rtos/zephyr","programFiles":["subsys/mgmt/ec_host_cmd/backends/ec_host_cmd_backend_shi_ite.c"],"programRoutines":[{"name":"shi_ite_cs_callback"},{"name":"shi_ite_int_handler"},{"name":"shi_ite_parse_header"}]}],"references":[{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/0636e65c825e810ad97f154606365870152d402f","name":"Fix commit","tags":["patch"]},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-4x98-6536-cwjv","name":"GHSA-4x98-6536-cwjv"}],"metrics":[{"format":"CVSS","cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H","baseScore":6.7,"baseSeverity":"MEDIUM"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-362","lang":"en","description":"race","type":"CWE"}]}],"providerMetadata":{"shortName":"zephyr","orgId":"e2e69745-5e70-4e92-8431-deb5529a81ad","dateUpdated":"2026-10-09T07:16:40.717Z"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-09T17:57:11.124067Z","id":"CVE-2026-19571","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-09T17:57:42.905Z"}}]}}}