CVE-2026-93811

Received Received - Intake

ksmbd ACL Memory Leak and Error Handling Vulnerability

Publication date: 2026-09-24

Last updated on: 2026-10-03

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: Fix acl.sd_buf memory leak and invalid sd_size error handling 1. When ndr_decode_v4_ntacl() fails, the code jumped to free_n_data which only freed n.data, skipping kfree(acl.sd_buf) and leaking the buffer. Zero-initialize struct xattr_ntacl acl, reorder error labels to out_free to release acl.sd_buf on all error paths. 2. if (acl.sd_size < sizeof(struct smb_ntsd)) is true, original code returned success without freeing sd_buf and left stale *pntsd. Set rc = -EINVAL before jumping to out_free to return error code and free buffer.

CVSS Scores

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Meta Information

Published

2026-09-24

Last Modified

2026-10-03

Generated

2026-10-15

AI Q&A

2026-09-25

EPSS Evaluated

2026-10-13

NVD

CVE-2026-93811

EUVD

EUVD-2026-86198

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This is a memory leak vulnerability in the Linux kernel's ksmbd module. When a specific function fails, memory allocated for access control data is not properly freed, causing a leak. Additionally, error handling could incorrectly return success while leaving stale data in memory.

Detection Guidance

This vulnerability is specific to the Linux kernel's ksmbd implementation and involves memory leaks and error handling in ACL processing. Detection requires checking for kernel logs or memory leaks related to ksmbd operations, particularly during SMB protocol interactions.

Impact Analysis

The memory leak could gradually consume system memory, potentially leading to performance degradation or crashes. The incorrect error handling might allow unauthorized access to stale data, posing security risks.

Compliance Impact

This vulnerability involves a memory leak in the ksmbd module of the Linux kernel due to improper handling of ACL buffer cleanup during error conditions. While it does not directly impact data privacy or security controls, such memory leaks could lead to resource exhaustion or instability in systems handling sensitive data. This may indirectly affect compliance with standards like GDPR or HIPAA by increasing the risk of service disruptions or unauthorized access if exploited.

Mitigation Strategies

Update the Linux kernel to the latest patched version that includes the fix for this ksmbd ACL memory leak and error handling issue. Monitor kernel logs for ksmbd-related errors or memory leaks as an indicator of exploitation or misconfiguration.

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