CVE-2026-53398
Received Received - Intake

NFSD SECINFO_NO_NAME Decode Error Leading to Use-After-Free

Publication date: 2026-07-19

Last updated on: 2026-07-19

Assigner: kernel.org

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().

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Meta Information

Published
2026-07-19
Last Modified
2026-07-19
Generated
2026-07-20
AI Q&A
2026-07-19
EPSS Evaluated
N/A
NVD
CVE-2026-53398
EUVD
EUVD-2026-45520

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves a flaw in the NFS server (NFSD) when handling SECINFO_NO_NAME requests. The issue occurs during error cleanup when the XDR stream is truncated, leaving a stale pointer (sin_exp) that gets improperly released, potentially causing a use-after-free scenario.

Detection Guidance

This vulnerability is specific to the Linux kernel's NFS server implementation. Detection requires checking the kernel version and NFS server configuration. Use commands like 'uname -a' to check the kernel version and 'systemctl status nfs-server' to verify if NFS is running. If your kernel version is vulnerable, update it immediately.

No direct detection commands are provided in the context. Focus on kernel version checks and NFS service monitoring.

Impact Analysis

If exploited, this could allow an attacker to cause a denial-of-service condition or execute arbitrary code on systems running vulnerable NFS server versions. Systems relying on NFS for file sharing could experience crashes or unauthorized access.

Compliance Impact

This vulnerability in the Linux kernel's NFS server (NFSD) could potentially lead to improper access control or information disclosure if exploited. While not directly tied to GDPR or HIPAA, such flaws may violate compliance requirements for data protection and access controls in regulated environments.

Mitigation Strategies

Update the Linux kernel to the latest stable version to ensure the fix is applied. Restart the NFS server service after updating. Monitor logs for SECINFO_NO_NAME decode errors to confirm the issue is resolved.

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