CVE-2023-54276nfsd: move init of percpu reply_cache_stats counters back to nfsd_init_net

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.

CVSS

Not yet scored

Weakness (CWE)

Not given

Known exploited

Not in CISA's KEV catalog

EPSS (exploitation in the next 30 days)

Not loaded for this CVE

Assigned by

Linux

NVD analysis

Deferred

Record last updated

May 11, 2026

First seen by InfoSec Signals

Oct 9, 2026

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