{"id":"CVE-2026-19184","published":"2026-10-05T09:17:12.907","lastModified":"2026-10-06T15:27:05.657","description":"The NXP GAU ADC driver (drivers/adc/adc_mcux_gau_adc.c) validated the caller-supplied sequence->buffer_size, which is expressed in bytes, against the number of active channels, which is a sample count. It then stored that byte count directly in data->results_length and used it in mcux_gau_adc_read_samples() as the number of uint16_t slots available. Because each conversion result occupies sizeof(uint16_t) bytes, a buffer that was accepted as \"large enough\" could be written with up to twice its size in bytes, so every sample past the buffer's midpoint was written out of bounds.\n\nadc_read() and adc_read_async() are Zephyr system calls. The syscall verifier in drivers/adc/adc_handlers.c only confirms that the caller owns buffer_size writable bytes (K_SYSCALL_MEMORY_WRITE); deciding whether that size is sufficient for the requested channels and extra_samplings is delegated entirely to the driver. On a build with CONFIG_USERSPACE=y, a user-mode thread that has been granted the ADC device object could therefore submit a deliberately half-sized buffer and cause the driver's work-queue handler — which runs in supervisor mode, outside the caller's MPU restrictions — to write ADC conversion results past the end of that buffer, at an address and for a length of the caller's choosing.\n\nThe overrun is bounded by the requested sequence: with sequence->options->extra_samplings set, the sampling loop walks the buffer pointer forward across every sampling, so the total overrun can reach the full size of the supplied buffer (kilobytes for a large extra_samplings). The written words are 16-bit ADC conversion results, so the content is only partially attacker-influenced (via the selected analog input, gain and resolution), but the destination and length are fully controlled — sufficient for kernel memory corruption, a crash, or a userspace-to-kernel privilege escalation. Builds without CONFIG_USERSPACE, or on SoCs other than NXP RW61x with the GAU ADC node enabled, are not exposed to the privilege boundary; there the same defect only causes a silent overflow when the application itself passes an undersized buffer.\n\nThe fix replaces the ad-hoc check with the shared adc_sequence_validate_buffer() helper (validating against num_channels * sizeof(uint16_t)), stores buffer_size / sizeof(uint16_t) in results_length, and corrects the loop bound to a post-decrement so exactly the available number of slots may be written.","cvssScore":8.4,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H","cwes":["CWE-787"],"vendors":[],"products":[],"references":[{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/82b11958065aa85f8644ddc318ff4a328d1443c8","tags":[]},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-j86w-mfgw-fxj9","tags":[]}],"exploitRefs":[{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/82b11958065aa85f8644ddc318ff4a328d1443c8","tags":[]},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-j86w-mfgw-fxj9","tags":[]}],"hasPoc":true,"ai":{"summary":"The flaw allows a user-mode thread to submit a half-sized buffer, causing the driver to write beyond the buffer's bounds, leading to potential data corruption or a buffer overflow.","exploitability":"Exploitation requires a user-mode thread with access to the ADC device object and knowledge of the buffer size. The exploit is moderately hard to carry out.","blast_radius":"If exploited, the flaw could lead to data corruption or a buffer overflow, potentially allowing an attacker to execute arbitrary code or cause a system crash.","remediation":"Disable the affected feature or restrict access to the ADC device object to prevent exploitation.","detection":"No reliable host or network indicator is derivable from the published description.","tags":["buffer-overflow","device-access","firmware-update"],"model":"qwen2.5:7b-instruct","analyzedAt":"2026-10-06T08:45:22.502Z"}}