# CVE-2026-97502: mmc: davinci: avoid NULL deref of host->data in IRQ handler

> A NULL pointer dereference in the Linux kernel's Davinci MMC driver IRQ handler allows local attackers to cause a system crash.

- **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:** 24 Sep 2026
- **Updated:** 3 Oct 2026
- **Also known as:** AZL-103793, BELL-CVE-2026-97502, DEBIAN-CVE-2026-97502, GHSA-7j63-m3c7-g76r, UBUNTU-CVE-2026-97502

## What is CVE-2026-97502?

CVE-2026-97502 is a vulnerability in Linux, published on 24 Sep 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:

mmc: davinci: avoid NULL deref of host->data in IRQ handler

mmc_davinci_irq() returns early only when both host->cmd and
host->data are NULL:

  if (host->cmd == NULL && host->data == NULL) {
          ...
          return IRQ_NONE;
  }

So we may legitimately reach the rest of the handler with
host->data == NULL (and therefore data == NULL). The DATDNE branch
already guards against this with an explicit "if (data != NULL)"
check, but the subsequent TOUTRD ("read data timeout") and
CRCWR/CRCRD ("data CRC error") branches dereference data
unconditionally:

  if (qstatus & MMCST0_TOUTRD) {
          data->error = -ETIMEDOUT;        <-- NULL deref
          ...
          davinci_abort_data(host, data);
  }

  if (qstatus & (MMCST0_CRCWR | MMCST0_CRCRD)) {
          data->error = -EILSEQ;           <-- NULL deref
          ...
  }

If either bit is set in qstatus while host->data is NULL, the kernel
will crash inside the IRQ handler. smatch flags this:

  drivers/mmc/host/davinci_mmc.c:933 mmc_davinci_irq() error: we
    previously assumed 'data' could be null (see line 914)

Gate both branches on a non-NULL data, matching the existing pattern
used by the DATDNE branch.

No functional change for callers where data is non-NULL, which is
the only case in which these branches did meaningful work before
this change.

## Which versions are affected by CVE-2026-97502?


## How do I fix CVE-2026-97502?

Apply the vendor's patch.

## Is CVE-2026-97502 being exploited?

There is no known exploitation of CVE-2026-97502 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-97502 and fix it if it is affected.

What it is: CVE-2026-97502 is a vulnerability in Linux, published on 24 Sep 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-2026-97502 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-2026-97502/ (Markdown: https://insights.sbomify.com/CVE-2026-97502/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-97502
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-97502
- OSV: https://osv.dev/vulnerability/CVE-2026-97502

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-97502/
Summaries are generated and may contain mistakes; the official description above is the record.