CVE-2026-31403: Linux Kernel

High severity, CVSS 7.8. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: NFSD: Hold net reference for the lifetime of /proc/fs/nfs/exports fd The /proc/fs/nfs/exports proc entry is created at module init and persists for the module's lifetime. exports_proc_open() captures the caller's current network namespace and stores its svc_export_cache in seq->private, but takes no reference on the namespace. If the namespace is subsequently torn down (e.g. container destruction after the opener does setns() to a different namespace), nfsd_net_exit() calls nfsd_export_shutdown() which frees the cache. Subsequent reads on the still-open fd dereference the freed cache_detail, walking a freed hash table. Hold a reference on the struct net for the lifetime of the open file descriptor. This prevents nfsd_net_exit() from running -- and thus prevents nfsd_export_shutdown() from freeing the cache -- while any exports fd is open. cache_detail already stores its net pointer (cd->net, set by cache_create_net()), so exports_release() can retrieve it without additional per-file storage.

Affected products

• Linux Linux Kernel: from 3.9, before 5.10.253 (fixed in 5.10.253); from 5.11, before 6.1.167 (fixed in 6.1.167); from 6.2, before 6.6.130 (fixed in 6.6.130); from 6.7, before 6.12.78 (fixed in 6.12.78); from 6.13, before 6.18.20 (fixed in 6.18.20); from 6.19, before 6.19.10 (fixed in 6.19.10); …

Published 2026-04-03. Last modified 2026-07-24.