CVE-2026-31403
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.
- Score
- CVSS 3.1 7.8 High
- Status
- Modified - 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- Published
- 2026-04-03
- Last modified
- 2026-10-19
- Weaknesses
- CWE-416
Affected products
- Linux Kernel (Linux)
- Simatic S7-1500 Cpu 1518-4 Pndp Mfp (Siemens)
- Simatic S7-1500 Cpu 1518f-4 Pndp Mfp (Siemens)
- Siplus S7-1500 Cpu 1518-4 Pndp Mfp (Siemens)
References
- https://git.kernel.org/stable/c/76740c28050dc6db2f5550f1325b00a11bbb3255
- https://git.kernel.org/stable/c/c7f406fb341d6747634b8b1fa5461656e5e56076
- https://git.kernel.org/stable/c/d1a19217995df9c7e4118f5a2820c5032fef2945
- https://git.kernel.org/stable/c/e3d77f935639e6ae4b381c80464c31df998d61f4
- https://git.kernel.org/stable/c/db4a9f99b12a7ee1c19d86c83a3b752c7effa6c6
- https://git.kernel.org/stable/c/6a8d70e2ad6aad2c345a5048edcb8168036f97d6
- https://git.kernel.org/stable/c/e7fcf179b82d3a3730fd8615da01b087cc654d0b
- https://cert-portal.siemens.com/productcert/html/ssa-082556.html
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-457936.html