CVE Catalog

CVE-2026-53396

HighCVSS 7.1
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.27%

19th percentile - higher than 19% of all known CVEs

Summary

In the Linux kernel, the nfsd4_create_file() function in the NFSD server has two vulnerabilities: a posix_acl memory leak and ignored errors during NFSv4-to-POSIX ACL conversion. These bugs can cause memory exhaustion and violate RFC 7530/8881.

Risk Assessment

The organization is at risk of system memory exhaustion through repeated CREATE requests with invalid ACL attributes, potentially leading to denial of service (DoS). Additionally, invalid ACL attributes are silently accepted, compromising access control integrity.

Recommendation

Immediately update the Linux kernel to a version containing the fix for CVE-2026-53396. If an update is not possible, restrict NFS server access to trusted clients only.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: nfsd: fix posix_acl leak and ignored error in nfsd4_create_file nfsd4_create_file() has two bugs in its ACL handling: The return value of nfsd4_acl_to_attr() is silently discarded. When the NFSv4-to-POSIX ACL conversion fails (e.g., -EINVAL for unsupported ACE types), the file is created without any ACL and the client receives NFS4_OK. This violates RFC 7530/8881 which require the server to reject unsupported attributes on CREATE. When start_creating() fails after ACL attributes have been populated in attrs (either via nfsd4_acl_to_attr or via ownership transfer from open->op_dpacl/op_pacl), the function jumps to out_write which skips nfsd_attrs_free(). The posix_acl allocations are leaked. A client can trigger this repeatedly with OPEN(CREATE), ACL attributes, and an invalid filename (e.g., longer than NAME_MAX). Fix both by capturing the nfsd4_acl_to_attr() return value and by changing the early error paths to jump to out instead of out_write. Initialize child to ERR_PTR(-EINVAL) so that end_creating() is safe to call even if start_creating() was never reached.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS