CVE-2026-64381

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Buffer Leak in Linux Kernel SMB Client

Publication date: 2026-07-25

Last updated on: 2026-09-08

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: Fix next buffer leak in receive_encrypted_standard() receive_encrypted_standard() allocates next_buffer before checking whether the number of compound PDUs already reached MAX_COMPOUND. If the limit check fails, the function returns immediately and the newly allocated next_buffer is not assigned to server->smallbuf/server->bigbuf, making it leaked. Move the MAX_COMPOUND check before allocating next_buffer.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-07-25

Last Modified

2026-09-08

Generated

2026-09-23

AI Q&A

2026-07-25

EPSS Evaluated

2026-09-22

NVD

CVE-2026-64381

EUVD

EUVD-2026-48925

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	From 5.11 (inc) to 5.15.212 (exc)
linux	linux_kernel	From 5.16 (inc) to 6.1.178 (exc)
linux	linux_kernel	From 6.2 (inc) to 6.6.145 (exc)
linux	linux_kernel	From 6.7 (inc) to 6.12.96 (exc)
linux	linux_kernel	From 6.13 (inc) to 6.18.39 (exc)
linux	linux_kernel	From 6.19 (inc) to 7.1.4 (exc)
linux	linux_kernel	From 4.19 (inc) to 5.10.261 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-787	The product writes data past the end, or before the beginning, of the intended buffer.

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves a buffer leak in the SMB client component. The function receive_encrypted_standard() allocates memory for a buffer before verifying if the maximum allowed compound PDUs (MAX_COMPOUND) has been reached. If the limit is exceeded, the function exits without assigning the buffer to the server's storage, causing a memory leak.

Detection Guidance

This vulnerability is specific to the Linux kernel's SMB client implementation and involves a buffer leak in receive_encrypted_standard(). Detection requires checking kernel logs for SMB-related errors or monitoring memory usage for unexpected buffer allocations. No direct commands are provided in the context to detect this issue.

Impact Analysis

This vulnerability could lead to memory leaks on systems using the Linux kernel's SMB client. Over time, this may cause system performance degradation or crashes due to exhaustion of available memory resources.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards as it pertains to a memory leak in the Linux kernel's SMB client component. Compliance impacts would depend on specific implementations and data processing contexts, which are not addressed by this CVE.

Mitigation Strategies

Update the Linux kernel to the latest patched version to resolve the buffer leak in smb client functionality.

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