Bug 2502222 (CVE-2026-53398)

Summary: CVE-2026-53398 kernel: NFSD: Fix SECINFO_NO_NAME decode error cleanup
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: high    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's Network File System Daemon (NFSD). The nfsd4_decode_secinfo_no_name() function does not properly initialize a pointer (sin_exp) before processing an incoming data stream. If the data stream is malformed or truncated, the uninitialized pointer can retain stale data from previous operations. This can lead to an improper cleanup operation, potentially causing system instability or a denial of service.
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Description OSIDB Bzimport 2026-07-19 13:02:38 UTC
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().