# CVE-2026-98677: iio: adc: ad_sigma_delta: fix use-after-free on unbind

CVE-2026-98677 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-98677, released October 19, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-98677
- Priority: Routine
- CVSS: 5.7 (Moderate)
- EPSS: 0.0021
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 18, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-98677

## Description

In the Linux kernel, the following vulnerability has been resolved:  iio: adc: ad_sigma_delta: fix use-after-free on unbind  ad_sd_buffer_postenable() allocates sigma_delta->samples_buf with devm_krealloc() at runtime, so its devres entry sits after all probe-time entries of the driver. devm resources are released in reverse allocation order, which means unbind frees samples_buf before iio_device_unregister() disables the buffers and detaches the trigger pollfunc. The data ready IRQ is still enabled at that point, so ad_sd_trigger_handler() can still run and memcpy() incoming samples into the freed samples_buf.  Fix this by preallocating the buffer in devm_ad_sd_setup_buffer_and_trigger(), before the triggered buffer and the IRQ are set up, so it is freed only after iio_device_unregister() has drained the trigger handler via free_irq(). Size it for the worst case of all sequencer slots being active; ad_sd_validate_scan_mask() already caps the number of active channels at num_slots.  This issue was found by an in-house static analysis tool.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 13.5 (trixie) | 6.12.113-1 | [DEBIAN-CVE-2026-98677](https://patchblox.com/security/data/fix/linux/debian-cve-2026-98677.md) | Oct 19, 2026 |
| Linux | linux Debian 14 | 7.2.10-1 | [DEBIAN-CVE-2026-98677](https://patchblox.com/security/data/fix/linux/debian-cve-2026-98677.md) | Oct 19, 2026 |
| Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.113-1~deb12u1 | [DEBIAN-CVE-2026-98677](https://patchblox.com/security/data/fix/linux/debian-cve-2026-98677.md) | Oct 19, 2026 |

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Data as of 2026-11-07T12:40:37Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo