CVE-2026-53398
CriticalCVSS 9.8Exploitation Probability (EPSS)
Low risk41th percentile - higher than 41% of all known CVEs
Summary
A vulnerability was found in the Linux kernel's NFSD server in the SECINFO_NO_NAME decode function. Improper initialization of the sin_exp structure before decoding may lead to using stale data from previous operations, causing an incorrect exp_put() call on an uninitialized pointer.
Risk Assessment
The risk involves potential memory leaks or system crashes (kernel panic) when handling malformed SECINFO_NO_NAME requests, which could be exploited for a DoS attack on the NFS server.
Recommendation
Immediately update the Linux kernel to a version containing the fix (commit 3fdc54646234 or later). Monitor for security patches from your distribution vendor.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: NFSD: Fix SECINFO_NO_NAME decode error cleanup nfsd4_decode_secinfo_no_name() currently initializes sin_exp after decoding sin_style. If the XDR stream is truncated, the decoder returns nfserr_bad_xdr before sin_exp is initialized. Since commit 3fdc54646234 ("NFSD: Reduce amount of struct nfsd4_compoundargs that needs clearing"), the inline iops array is not cleared between RPC calls. A failed SECINFO_NO_NAME decode can therefore leave sin_exp holding stale union contents from a previous operation. The error response path still invokes nfsd4_secinfo_no_name_release(), which calls exp_put() on a non-NULL sin_exp. Initialize sin_exp before the first failable decode step, matching nfsd4_decode_secinfo().