CVE-2026-53398
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().
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A critical vulnerability (CVSS 9.8) has been identified in the Linux kernel's NFS server (NFSD). A remote attacker can trigger memory corruption through a crafted, truncated XDR stream, potentially leading to a kernel-level crash or remote code execution. This affects systems running the kernel's built-in NFS server.
Relevant roles
Severity
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HEPSS
Technical description
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().
References
- https://git.kernel.org/stable/c/161d1aaeb04d620d3692639700512bb5038c1e10
- https://git.kernel.org/stable/c/1e04be34cafae119e82bcaccd6d28a20f72a3647
- https://git.kernel.org/stable/c/46eb17d45be69d28c7a23ea03283b207426a8232
- https://git.kernel.org/stable/c/49de5d31dd8fdebf78bdeaf196b0ca5cd5c75439
- https://git.kernel.org/stable/c/5ec37edcb534f3fc92304be236d37f08e6545585
- https://git.kernel.org/stable/c/8836405abdc53ca3dd5fc68b2cf6f8f012fad011
- https://git.kernel.org/stable/c/9e18e83b8846a5c3fe13fc8a464b4865d33996c6
- https://git.kernel.org/stable/c/c8a24effd96d4779e2ad779654682304491c55a5