{"id":"CVE-2026-19571","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-19571","generatedAt":"2026-10-28T02:19:58.665Z","title":"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.","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.","published":"2026-10-09T08:16:55.000Z","lastModified":"2026-10-09T18:17:08.000Z","status":"Awaiting Analysis","sourceIdentifier":"vulnerabilities@zephyrproject.org","cvss":{"version":"3.1","score":6.7,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H"},"cwe":["CWE-362"],"affected":[],"epss":{"score":0.00091,"percentile":0.00461,"date":"2026-10-26","history":[{"date":"2026-10-09","score":0.00091,"percentile":0.00457}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.09%). Track it; it rarely justifies an emergency change on its own."},"changes":[{"kind":"new","label":"New CVE","at":"2026-10-09T08:16:55.000Z","detail":{"score":"6.7","severity":"MEDIUM","publishedAt":"2026-10-09T08:16:54.817Z"},"summary":"New CVE, medium severity (CVSS 6.7)."}],"references":[{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/0636e65c825e810ad97f154606365870152d402f","source":"vulnerabilities@zephyrproject.org"},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-4x98-6536-cwjv","source":"vulnerabilities@zephyrproject.org"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-19571","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}