CVE-2026-64091: Software Security Vulnerability Vulnerability

CRITICAL
Advisory Identifier: GHSA-r4m5-xwcp-9p7w
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CVSS 9.8
CWE-367
Published
Advisory Summary

CVE-2026-64091 is a CRITICAL (CVSS 9.8) security vulnerability vulnerability (CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-64091 at a Glance

CVE Identifier CVE-2026-64091
GHSA Identifier GHSA-r4m5-xwcp-9p7w
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 9.8

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

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
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-2026-64091

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-2026-64091, 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-367: Time-of-check Time-of-use (TOCTOU) Race Condition, where the product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check. 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: batman-adv: tt: fix TOCTOU race for reported vlans The local TT based TVLV is generated by first checking the number of VLANs which have at least one TT entry. A new buffer with the correct size for the VLANs is then allocated. Only then, the list of VLANs s used to fill the VLAN entries in the buffer. During this time, the meshif_vlan_list_lock is held. But the actual number of TT entries of each VLAN can still increase during this time - just not the number of VLANs in the list. But the prefilter used in the buffer size calculation might still cause an increase of the number of VLANs which need to be stored. Simply because a VLAN might now suddenly have at least one entry when it had none in the pre-alloc check - and then needs to occupy space which was not allocated. It is better to overestimate the buffer size at the beginning and then fill the buffer only with the VLANs which are not empty.

References

NVD — CVE-2026-64091 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-64091
git.kernel.org/stable/c/211ea59988... WEB
https://git.kernel.org/stable/c/211ea59988e1cba43cb0367ad65d379b56f9c3bd
git.kernel.org/stable/c/4cc85aec8d... WEB
https://git.kernel.org/stable/c/4cc85aec8d3c9ab4dc716dc9f1ed36fca16b227f
git.kernel.org/stable/c/65a1e67339... WEB
https://git.kernel.org/stable/c/65a1e67339aa8c95ac544b796946af388930ee23
git.kernel.org/stable/c/724a8eb415... WEB
https://git.kernel.org/stable/c/724a8eb4155669797c96b70d70e354284ae3b5a8
git.kernel.org/stable/c/94d2700501... WEB
https://git.kernel.org/stable/c/94d27005016be15ffc638b2ecbc4d58805ad7b48
git.kernel.org/stable/c/9a9c859457... WEB
https://git.kernel.org/stable/c/9a9c859457bc440a55773e01ff18b1bb5bab6836
git.kernel.org/stable/c/b4d4efd4e3... WEB
https://git.kernel.org/stable/c/b4d4efd4e351593c81e9293d4b4408d244fa5ee7
git.kernel.org/stable/c/e4236bf3ec... WEB
https://git.kernel.org/stable/c/e4236bf3ec8d6bb15d0d8d825dcf9933a7d6666b

Frequently Asked Questions

What is CVE-2026-64091?
CVE-2026-64091 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-64091?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-64091?
CVE-2026-64091 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-64091?
CVE-2026-64091 is classified under CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition (The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.).
How can I check Maven dependencies for CVE-2026-64091?
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-r4m5-xwcp-9p7w",
  "modified" : "2026-07-20T15:31:59Z",
  "published" : "2026-07-19T18:31:51Z",
  "aliases" : [ "CVE-2026-64091" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: tt: fix TOCTOU race for reported vlans\n\nThe local TT based TVLV is generated by first checking the number of VLANs\nwhich have at least one TT entry. A new buffer with the correct size for\nthe VLANs is then allocated. Only then, the list of VLANs s used to fill\nthe VLAN entries in the buffer. During this time, the meshif_vlan_list_lock\nis held. But the actual number of TT entries of each VLAN can still\nincrease during this time - just not the number of VLANs in the list.\n\nBut the prefilter used in the buffer size calculation might still cause an\nincrease of the number of VLANs which need to be stored. Simply because a\nVLAN might now suddenly have at least one entry when it had none in the\npre-alloc check - and then needs to occupy space which was not allocated.\n\nIt is better to overestimate the buffer size at the beginning and then fill\nthe buffer only with the VLANs which are not empty.",
  "severity" : [ {
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  "database_specific" : {
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    "severity" : "CRITICAL",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-07-19T16:17:49Z"
  }
}