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

> A use-after-free in the Linux kernel AD Sigma-Delta ADC driver allows attackers to execute code or cause a denial of service via device unbinding.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 18 Oct 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-108731, BELL-CVE-2026-98677, DEBIAN-CVE-2026-98677, GHSA-852j-fqfh-mmqj, UBUNTU-CVE-2026-98677

## What is CVE-2026-98677?

CVE-2026-98677 is an use after free vulnerability in Linux, published on 18 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

## Which versions are affected by CVE-2026-98677?


## How do I fix CVE-2026-98677?

Apply the vendor's patch.

## Is CVE-2026-98677 being exploited?

There is no known exploitation of CVE-2026-98677 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98677 and fix it if it is affected.

What it is: CVE-2026-98677 is an use after free vulnerability in Linux, published on 18 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-98677 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-98677/ (Markdown: https://insights.sbomify.com/CVE-2026-98677/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98677
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98677
- OSV: https://osv.dev/vulnerability/CVE-2026-98677

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98677/
Summaries are generated and may contain mistakes; the official description above is the record.