# CVE-2026-64502: linux: In the Linux kernel, the following vulnerability has been resolved:  iio: adc: ad_sigma_delta: fix clear_pending_even...

CVE-2026-64502 is fixed in linux on 1 platform by DEBIAN-CVE-2026-64502 (version 7.1.4-1), released August 7, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-64502
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0017
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 25, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  iio: adc: ad_sigma_delta: fix clear_pending_event for registerless devices  ad_sigma_delta_clear_pending_event() falls through to the status register read path for devices with has_registers = false and no rdy_gpiod. For such devices, ad_sd_read_reg() skips the address byte entirely and clocks raw MISO bytes with no address phase — making it byte-for-byte identical to reading conversion data. If a pending conversion result is present, this partially consumes it and corrupts the data stream for the subsequent ad_sd_read_reg() call in ad_sigma_delta_single_conversion().  Furthermore, with num_resetclks = 0 on these devices, data_read_len evaluates to 0. If the clocked byte has bit 7 clear, pending_event is set and the code attempts memset(data + 2, 0xff, 0 - 1), overflowing to SIZE_MAX and corrupting the heap.  Fix by returning 0 immediately when neither rdy_gpiod nor has_registers is set. This is safe for all current registerless devices: ad7191 and ad7780 (with powerdown GPIO) are reset between conversions by CS deassertion, so there is no stale result to drain; ad7780 (without powerdown GPIO) and max11205 are continuously-converting and cycle ~DRDY at the output data rate regardless of whether the previous result was read, so the next falling edge fires naturally.  A future registerless device that holds ~DRDY asserted until data is read would be broken by this early return and would require either num_resetclks set or a rdy-gpio.  The same heap corruption is reachable on any device with rdy_gpiod set but num_resetclks = 0: if the GPIO indicates a pending event, the drain path executes memset(data + 2, 0xff, 0 - 1) regardless of has_registers. Add an explicit data_read_len == 0 guard after the pending event check; the stale result is then consumed by the first ad_sd_read_reg() call in ad_sigma_delta_single_conversion().

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.1.4-1 | [DEBIAN-CVE-2026-64502](https://patchblox.com/security/data/fix/linux/debian-cve-2026-64502.md) | Aug 7, 2026 |

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