CVE-2026-53396

What it is

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.

At a glance

Exploitability

Can be exploited over the network with a low-privilege account. High risk of service disruption.

Exploit odds

0.4% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-07-19 12:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-08-17 05:17 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.4% in the next 30 days (EPSS).
• Severity: 7.1 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-07-19 12:16 UTC

Last modified

2026-08-17 05:17 UTC

Exploit probability

0.4% · EPSS, next 30 days

Weakness

CWE-401

Record status

Analyzed

Affected

• Linux Kernel < 7.1.3

Attack profile CVSS 3.1 · 7.1

Attack vector

Network

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-53396.md and follow it. Check whether this project is affected by CVE-2026-53396. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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