CVE-2026-56721: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-m39h-f7fw-54qw
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CVSS 8.8
CWE-639
Published
Advisory Summary

CVE-2026-56721 is a HIGH (CVSS 8.8) security vulnerability vulnerability (CWE-639: Authorization Bypass Through User-Controlled Key) affecting Software libraries in the Maven ecosystem. The weakness occurs when the system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-56721 at a Glance

CVE Identifier CVE-2026-56721
GHSA Identifier GHSA-m39h-f7fw-54qw
Severity HIGH
CVSS v3.1 Base Score 8.8
CWE Classification CWE-639: Authorization Bypass Through User-Controlled Key
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-2026-56721

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-2026-56721, 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-639: Authorization Bypass Through User-Controlled Key, where the system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. 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

CamaleonCMS version 2.9.2 and earlier contains a privilege escalation vulnerability via insecure direct object reference (IDOR) that allows authenticated low-privileged attackers to overwrite any user's credentials by exploiting a parameter confusion flaw between the authorization filter and action body in the UsersController. Attackers can send a PATCH request to the updated_ajax endpoint setting params[:id] to their own user ID to pass the self-authorization check while simultaneously setting params[:user_id] to a victim's ID, causing the controller to load and mutate the victim's account, including overwriting administrator passwords to achieve full site takeover.

References

NVD — CVE-2026-56721 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-56721
Software Source Repository REPOSITORY
https://github.com/owen2345/camaleon-cms/pull/1185
Security Fix Commit FIX COMMIT
https://github.com/owen2345/camaleon-cms/commit/26345034523a505cb01615509b7f0a665e89ae3e
Software Source Repository REPOSITORY
https://github.com/owen2345/camaleon-cms
www.vulncheck.com/advisories/camaleon... WEB
https://www.vulncheck.com/advisories/camaleoncms-privilege-escalation-via-parameter-confusion-in-userscontroller

Frequently Asked Questions

What is CVE-2026-56721?
CVE-2026-56721 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-639: Authorization Bypass Through User-Controlled Key.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-56721?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-56721?
CVE-2026-56721 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-2026-56721?
CVE-2026-56721 is classified under CWE-639: Authorization Bypass Through User-Controlled Key (The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.).
How can I check Maven dependencies for CVE-2026-56721?
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-m39h-f7fw-54qw",
  "modified" : "2026-08-11T18:30:48Z",
  "published" : "2026-08-11T18:30:48Z",
  "aliases" : [ "CVE-2026-56721" ],
  "details" : "CamaleonCMS version 2.9.2 and earlier contains a privilege escalation vulnerability via insecure direct object reference (IDOR) that allows authenticated low-privileged attackers to overwrite any user's credentials by exploiting a parameter confusion flaw between the authorization filter and action body in the UsersController. Attackers can send a PATCH request to the updated_ajax endpoint setting params[:id] to their own user ID to pass the self-authorization check while simultaneously setting params[:user_id] to a victim's ID, causing the controller to load and mutate the victim's account, including overwriting administrator passwords to achieve full site takeover.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/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-2026-56721"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/owen2345/camaleon-cms/pull/1185"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/owen2345/camaleon-cms/commit/26345034523a505cb01615509b7f0a665e89ae3e"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/owen2345/camaleon-cms"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/camaleoncms-privilege-escalation-via-parameter-confusion-in-userscontroller"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-639" ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-08-11T16:17:33Z"
  }
}