CVE-2025-39819
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-09-16

Last updated on: 2025-11-03

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: fs/smb: Fix inconsistent refcnt update A possible inconsistent update of refcount was identified in `smb2_compound_op`. Such inconsistent update could lead to possible resource leaks. Why it is a possible bug: 1. In the comment section of the function, it clearly states that the reference to `cfile` should be dropped after calling this function. 2. Every control flow path would check and drop the reference to `cfile`, except the patched one. 3. Existing callers would not handle refcount update of `cfile` if -ENOMEM is returned. To fix the bug, an extra goto label "out" is added, to make sure that the cleanup logic would always be respected. As the problem is caused by the allocation failure of `vars`, the cleanup logic between label "finished" and "out" can be safely ignored. According to the definition of function `is_replayable_error`, the error code of "-ENOMEM" is not recoverable. Therefore, the replay logic also gets ignored.
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Meta Information
Published
2025-09-16
Last Modified
2025-11-03
Generated
2026-06-16
AI Q&A
2025-09-16
EPSS Evaluated
2026-06-15
NVD
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel 6.1.153
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Exploitability
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CWE ID Description
CWE-UNKNOWN
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Executive Summary

This vulnerability is an inconsistent reference count update in the Linux kernel's SMB2 compound operation function (smb2_compound_op). Specifically, the reference to a file object (cfile) is not always properly dropped when an allocation failure (-ENOMEM) occurs, leading to potential resource leaks. The fix ensures that cleanup logic is always executed to prevent these leaks.

Impact Analysis

The vulnerability can lead to resource leaks in the Linux kernel when handling SMB2 operations. Resource leaks may degrade system performance or stability over time, potentially causing system slowdowns or crashes if resources are exhausted.

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