CVE-2026-93229

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

nfsd: add missing read barrier to rpc_status_get dumpit seqcount retry

The hand-rolled seqcount-like protocol in nfsd_nl_rpc_status_get_dumpit()

is missing a read memory barrier (smp_rmb) before its second counter

check. The standard kernel read_seqcount_retry() includes smp_rmb()

to ensure that all data reads complete before the counter is re-checked.

Without this barrier, on weakly-ordered architectures (ARM, POWER),

the CPU may reorder field reads past the second counter check, making

the retry logic ineffective: it could observe a consistent counter pair

while reading fields that have been concurrently modified by the writer.

Add smp_rmb() before the second counter check to order the field reads

ahead of it, matching the barrier semantics of the standard seqcount

read-side. The begin-side smp_load_acquire() already pairs with the

smp_store_release() in nfsd_dispatch(); with the smp_rmb() now ordering

the fiel

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References