CVE-2026-21588: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-4848-75hf-436m
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CWE-400
Published
Advisory Summary

CVE-2026-21588 is a HIGH security vulnerability vulnerability (CWE-400: Uncontrolled Resource Consumption) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product does not properly control the allocation and maintenance of a limited resource.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-21588 at a Glance

CVE Identifier CVE-2026-21588
GHSA Identifier GHSA-4848-75hf-436m
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-400: Uncontrolled Resource Consumption
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

How to Fix CVE-2026-21588

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-2026-21588, 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-400: Uncontrolled Resource Consumption, where the product does not properly control the allocation and maintenance of a limited resource. 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

This High severity DoS (Denial of Service) vulnerability was introduced in versions 8.9.0, 9.0.1, 9.1.0, 9.2.0, 9.3.1, 9.4.0, 9.5.1, 10.0.2, 10.1.0, and 10.2.0 of Confluence Data Center. This DoS (Denial of Service) vulnerability, with a CVSS Score of 7.1, allows an authenticated attacker to cause a resource to be unavailable for its intended users by temporarily or indefinitely disrupting services of a host connected to a network. Atlassian recommends that Confluence Data Center customers upgrade to latest version, if you are unable to do so, upgrade your instance to one of the specified supported fixed versions: Confluence Data Center 9.2: Upgrade to a release greater than or equal to 9.2.24 Confluence Data Center 10.2: Upgrade to a release greater than or equal to 10.2.17 See the release notes ([https://confluence.atlassian.com/doc/confluence-release-notes-327.html]). You can download the latest version of Confluence Data Center from the download center ([https://www.atlassian.com/software/confluence/download-archives]). This vulnerability was reported via our Penetration Testing program.

References

NVD — CVE-2026-21588 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-21588
confluence.atlassian.com/pages/viewpage.acti... WEB
https://confluence.atlassian.com/pages/viewpage.action?pageId=1822852209
jira.atlassian.com/browse/confserver-1... WEB
https://jira.atlassian.com/browse/CONFSERVER-104451

Frequently Asked Questions

What is CVE-2026-21588?
CVE-2026-21588 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-400: Uncontrolled Resource Consumption.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-21588?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What CWE is associated with CVE-2026-21588?
CVE-2026-21588 is classified under CWE-400: Uncontrolled Resource Consumption (The product does not properly control the allocation and maintenance of a limited resource.).
How can I check Maven dependencies for CVE-2026-21588?
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 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-4848-75hf-436m",
  "modified" : "2026-09-15T18:32:32Z",
  "published" : "2026-09-15T18:32:32Z",
  "aliases" : [ "CVE-2026-21588" ],
  "details" : "This High severity DoS (Denial of Service) vulnerability was introduced in versions 8.9.0, 9.0.1, 9.1.0, 9.2.0, 9.3.1, 9.4.0, 9.5.1, 10.0.2, 10.1.0, and 10.2.0 of Confluence Data Center.\n\nThis DoS (Denial of Service) vulnerability, with a CVSS Score of 7.1, allows an authenticated attacker to cause a resource to be unavailable for its intended users by temporarily or indefinitely disrupting services of a host connected to a network.\n\nAtlassian recommends that Confluence Data Center customers upgrade to latest version, if you are unable to do so, upgrade your instance to one of the specified supported fixed versions:\n Confluence Data Center 9.2: Upgrade to a release greater than or equal to 9.2.24\n\n Confluence Data Center 10.2: Upgrade to a release greater than or equal to 10.2.17\n\nSee the release notes ([https://confluence.atlassian.com/doc/confluence-release-notes-327.html]). You can download the latest version of Confluence Data Center from the download center ([https://www.atlassian.com/software/confluence/download-archives]).\n\nThis vulnerability was reported via our Penetration Testing program.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-21588"
  }, {
    "type" : "WEB",
    "url" : "https://confluence.atlassian.com/pages/viewpage.action?pageId=1822852209"
  }, {
    "type" : "WEB",
    "url" : "https://jira.atlassian.com/browse/CONFSERVER-104451"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-400" ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-09-15T17:17:12Z"
  }
}