CVE-2026-64396: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-w2fg-c334-xw3q
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CVSS 8.8
CWE-416
Published
Advisory Summary

CVE-2026-64396 is a HIGH (CVSS 8.8) security vulnerability vulnerability (CWE-416: Use After Free) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product reuses or references memory after it has been freed. at some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-64396 at a Glance

CVE Identifier CVE-2026-64396
GHSA Identifier GHSA-w2fg-c334-xw3q
Severity HIGH
CVSS v3.1 Base Score 8.8
CWE Classification CWE-416: Use After Free
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 8.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-64396

To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-64396, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree

Analyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-416: Use After Free, where the product reuses or references memory after it has been freed. at some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer. In Software, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix UAF of struct file_lock in SMB2_LOCK deferred-lock cancellation When a blocking byte-range lock request is deferred in the FILE_LOCK_DEFERRED path, ksmbd registers the asynchronous work into the connection's async_requests list via setup_async_work(). The cancel callback smb2_remove_blocked_lock() holds a reference to the flock. If the lock waiter is subsequently woken up but the work state is no longer KSMBD_WORK_ACTIVE (e.g., due to a concurrent cancellation), the cleanup path calls locks_free_lock(flock) without dequeuing the work from the async_requests list. Concurrently, smb2_cancel() walks the list under conn->request_lock and invokes the cancel callback, which then dereferences the already freed 'flock'. This leads to a slab-use-after-free inside __wake_up_common. Fix this by restructuring the cleanup logic after the worker returns from ksmbd_vfs_posix_lock_wait(). Move list_del(&smb_lock->llist) and release_async_work(work) to the top of the cleanup block. This guarantees that the async work is completely dequeued and serialized under conn->request_lock before locks_free_lock(flock) is called, rendering the flock unreachable for any concurrent smb2_cancel().

References

NVD — CVE-2026-64396 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-64396
git.kernel.org/stable/c/367c42a611... WEB
https://git.kernel.org/stable/c/367c42a611fe488b7b03f1f6737f4dee0e8b20a2
git.kernel.org/stable/c/463bbd7969... WEB
https://git.kernel.org/stable/c/463bbd79698513af4dad50fe1c573825f297ca2e
git.kernel.org/stable/c/5aa1cb0115... WEB
https://git.kernel.org/stable/c/5aa1cb01155f96824003baf7997cdf1f150caba3
git.kernel.org/stable/c/5c75275c0f... WEB
https://git.kernel.org/stable/c/5c75275c0fc9a2deb0d8f5604edcb16f288171c8
git.kernel.org/stable/c/7703fd9aba... WEB
https://git.kernel.org/stable/c/7703fd9aba1f2483c8e55f9ff73b7663e0761ed9
git.kernel.org/stable/c/d20d1c8ba5... WEB
https://git.kernel.org/stable/c/d20d1c8ba5765d1d12eefc0aee6385ab3f240e1e

Frequently Asked Questions

What is CVE-2026-64396?
CVE-2026-64396 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-416: Use After Free.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-64396?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-64396?
CVE-2026-64396 has a CVSS v3.1 base score of 8.8 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-64396?
CVE-2026-64396 is classified under CWE-416: Use After Free (The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.).
How can I check Maven dependencies for CVE-2026-64396?
Run the dependency tree command: 'mvn dependency:tree'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
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  "id" : "GHSA-w2fg-c334-xw3q",
  "modified" : "2026-07-27T06:30:36Z",
  "published" : "2026-07-25T12:31:34Z",
  "aliases" : [ "CVE-2026-64396" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix UAF of struct file_lock in SMB2_LOCK deferred-lock cancellation\n\nWhen a blocking byte-range lock request is deferred in the\nFILE_LOCK_DEFERRED path, ksmbd registers the asynchronous work into\nthe connection's async_requests list via setup_async_work(). The cancel\ncallback smb2_remove_blocked_lock() holds a reference to the flock.\n\nIf the lock waiter is subsequently woken up but the work state is no\nlonger KSMBD_WORK_ACTIVE (e.g., due to a concurrent cancellation), the\ncleanup path calls locks_free_lock(flock) without dequeuing the work from\nthe async_requests list. Concurrently, smb2_cancel() walks the list\nunder conn->request_lock and invokes the cancel callback, which then\ndereferences the already freed 'flock'. This leads to a slab-use-after-free\ninside __wake_up_common.\n\nFix this by restructuring the cleanup logic after the worker returns\nfrom ksmbd_vfs_posix_lock_wait(). Move list_del(&smb_lock->llist) and\nrelease_async_work(work) to the top of the cleanup block. This guarantees\nthat the async work is completely dequeued and serialized under\nconn->request_lock before locks_free_lock(flock) is called, rendering\nthe flock unreachable for any concurrent smb2_cancel().",
  "severity" : [ {
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    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
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  "database_specific" : {
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    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-07-25T10:17:23Z"
  }
}