{"schema":"threatline.record/2","record":{"id":"CVE-2026-19571","aliases":["GHSA-4x98-6536-cwjv"],"summary":"Race condition in ITE IT8xxx2 SHI host-command backend lets a second SPI request write an unvalidated length into the in-flight request buffer","details":"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.","categories":["Unclassified"],"product":"zephyr","vendor":"zephyrproject","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-19571","source_modified_at":"2026-10-09T17:57:42.905Z","fetched_at":"2026-10-23T18:48:36.087640Z","product":"zephyr","vendor":"zephyrproject","versions":[{"version":"3.3.0","status":"affected","lessThan":"4.5.0","versionType":"semver"}],"defaultStatus":"unaffected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-19571","source_modified_at":"2026-10-09T17:57:42.905Z","fetched_at":"2026-10-23T18:48:36.087640Z","package":{"name":"zephyr","ecosystem":null},"version":"4.5.0","basis":"first unaffected version stated in the CVE record"}],"cvss":6.7,"severity":"Medium","kev":{"listed":false},"epss":{"probability":0.00091,"percentile":0.00451,"score_date":"2026-10-23"},"published_at":"2026-10-09T07:16:40.717Z","modified_at":"2026-10-09T17:57:42.905Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-19571","fetched_at":"2026-10-23T18:48:36.087640Z","source_modified_at":"2026-10-09T17:57:42.905Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-19571","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://github.com/zephyrproject-rtos/zephyr/commit/0636e65c825e810ad97f154606365870152d402f","tags":["patch"]},{"source":"CVE List","url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-4x98-6536-cwjv"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CVE List","ssvc":{"exploitation":"none","automatable":"no","technical_impact":"partial","assessed_at":"2026-10-09T17:57:11.124067Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":null,"confidence":"unknown","reviewed":false},"change_timestamp":"2026-10-09T17:57:42.905Z","content_hash":"96069ecd7ba491c356f31ef5ef7c2240a1e238944e753c5fd1d5e44e6c904a8b"}}