CVE-2025-38023: 
Linux Kernel vulnerability analysis and mitigation

CVE-2025-38023 is a vulnerability discovered in the Linux kernel affecting the NFS (Network File System) implementation. The vulnerability was disclosed on June 18, 2025, and involves the handling of failure in nfs_get_lock_context within the unlock path (NVD, Wiz).

The vulnerability occurs when memory is insufficient, causing the allocation of nfs_lock_context in nfs_get_lock_context() to fail and return -ENOMEM. When an nfs4_unlockdata structure (whose l_ctx member has been set to -ENOMEM) is incorrectly treated as valid and proceeds to execute rpc_run_task(), it triggers a NULL pointer dereference in nfs4_locku_prepare. This can lead to a kernel NULL pointer dereference at address 0x0000000c (NVD, Wiz).

The vulnerability can result in a kernel crash due to NULL pointer dereference, potentially affecting system stability and availability. The issue manifests when the system is under memory pressure conditions, making it particularly concerning for production environments (Wiz).

The fix involves freeing the allocated nfs4_unlockdata when nfs_get_lock_context() fails and returning NULL to terminate subsequent rpc_run_task, thereby preventing the NULL pointer dereference. Fixed versions are available in Debian bookworm 6.1.140-1, trixie 6.12.32-1, and sid 6.12.33-1 (Debian).