{"id":"CVE-2026-14986","title":"The ITE it51xxx I2C driver, when operating as an I2C target (slave) in buffer mode (CONFIG_I2C_TARGET + CONFIG_I2C_TARGET_BUFFER_MODE), copies host-supplied write data into the fixed-size data->target_in_buffer inside its target FIFO int…","summary":"The ITE it51xxx I2C driver, when operating as an I2C target (slave) in buffer mode (CONFIG_I2C_TARGET + CONFIG_I2C_TARGET_BUFFER_MODE), copies host-supplied write data into the fixed-size data->target_in_buffer inside its target FIFO int…","severity":"medium","cvss":6.8,"cvssVector":"CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-787"],"vendor":"zephyrproject","product":"zephyr","affected":["zephyr >= 4.2.0 < 4.4.2"],"published":"2026-09-14","updated":"2026-09-18","sourceUpdated":"2026-09-18T19:11:57.760","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-14986","references":[{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/eac92173cf13bba4e6c6eea3460ee6085513d86d","label":"vulnerabilities@zephyrproject.org"},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-jmjj-w736-fw2j","label":"vulnerabilities@zephyrproject.org"}],"tags":["nvd","cve.org"],"epss":0.00182,"epssPercentile":0.0806,"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-09-15T13:42:52.993721Z"},"ingestedAt":"2026-09-14T23:17:06.521Z","slug":"CVE-2026-14986","body":"## Overview\n\nThe ITE it51xxx I2C driver, when operating as an I2C target (slave) in buffer mode (CONFIG_I2C_TARGET + CONFIG_I2C_TARGET_BUFFER_MODE), copies host-supplied write data into the fixed-size data->target_in_buffer inside its target FIFO interrupt handler target_i2c_isr_fifo() in drivers/i2c/i2c_ite_it51xxx.c. The copy loop stores to target_in_buffer[i + data->w_index] and only checks data->w_index against sizeof(data->target_in_buffer) after the write has already completed, so the bounds check cannot prevent the overflow.\n\nThe running index data->w_index accumulates count bytes on every FIFO-fill interrupt of an ongoing transaction and is reset to zero only on a STOP or timeout condition. An I2C host that streams a single write transaction longer than the buffer (default CONFIG_I2C_TARGET_IT51XXX_MAX_BUF_SIZE = 256 bytes) drives data->w_index past the end of the buffer, and each subsequent host byte is written out of bounds into the adjacent data->target_out_buffer and following static device data.\n\nThe trigger is a malicious or misbehaving I2C master on the same bus (for example a compromised application processor or a rogue device on an exposed I2C bus); no software privilege on the victim is required and the handler runs in the target's kernel/firmware context. Because both the written values and the overflow length are attacker-controlled, this is an out-of-bounds write that can crash the controller or be shaped toward code execution. The fix adds a pre-write bounds check in target_i2c_fifo_read_to_buf() that aborts and resets the FIFO before any out-of-bounds store.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":37,"depthScoreParts":{"impact":37.4,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}