{"cve":"CVE-2026-64502","nvd":{"published":"2026-07-25T10:17:36.200","modified":"2026-08-17T05:17:56.263","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\niio: adc: ad_sigma_delta: fix clear_pending_event for registerless devices\n\nad_sigma_delta_clear_pending_event() falls through to the status register\nread path for devices with has_registers = false and no rdy_gpiod. For\nsuch devices, ad_sd_read_reg() skips the address byte entirely and clocks\nraw MISO bytes with no address phase — making it byte-for-byte identical\nto reading conversion data. If a pending conversion result is present,\nthis partially consumes it and corrupts the data stream for the subsequent\nad_sd_read_reg() call in ad_sigma_delta_single_conversion().\n\nFurthermore, with num_resetclks = 0 on these devices, data_read_len\nevaluates to 0. If the clocked byte has bit 7 clear, pending_event is set\nand the code attempts memset(data + 2, 0xff, 0 - 1), overflowing to\nSIZE_MAX and corrupting the heap.\n\nFix by returning 0 immediately when neither rdy_gpiod nor has_registers\nis set. This is safe for all current registerless devices: ad7191 and\nad7780 (with powerdown GPIO) are reset between conversions by CS\ndeassertion, so there is no stale result to drain; ad7780 (without\npowerdown GPIO) and max11205 are continuously-converting and cycle ~DRDY\nat the output data rate regardless of whether the previous result was\nread, so the next falling edge fires naturally.\n\nA future registerless device that holds ~DRDY asserted until data is read\nwould be broken by this early return and would require either\nnum_resetclks set or a rdy-gpio.\n\nThe same heap corruption is reachable on any device with rdy_gpiod set\nbut num_resetclks = 0: if the GPIO indicates a pending event, the drain\npath executes memset(data + 2, 0xff, 0 - 1) regardless of has_registers.\nAdd an explicit data_read_len == 0 guard after the pending event check;\nthe stale result is then consumed by the first ad_sd_read_reg() call in\nad_sigma_delta_single_conversion().","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":[],"references":["https://git.kernel.org/stable/c/3394e0b3328422431cadaf314fa58d3717ed4936","https://git.kernel.org/stable/c/3bceb26dfaf7ba805b459e41c1d0ba916862dade","https://git.kernel.org/stable/c/91bc6767a4f55dc470d8a56b55b9f2ea09094efe"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:46:40.600842820+00:00"},"epss":{"cve":"CVE-2026-64502","score":0.00173,"percentile":0.06759,"date":"2026-11-01"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}