CVE-2026-18933: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-cc9f-29gq-5x7c
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CVSS 7.2
CWE-434
Published
Advisory Summary

CVE-2026-18933 is a HIGH (CVSS 7.2) security vulnerability vulnerability (CWE-434: Unrestricted Upload of File with Dangerous Type) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product allows the upload or transfer of dangerous file types that are automatically processed within its environment.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-18933 at a Glance

CVE Identifier CVE-2026-18933
GHSA Identifier GHSA-cc9f-29gq-5x7c
Severity HIGH
CVSS v3.1 Base Score 7.2
CWE Classification CWE-434: Unrestricted Upload of File with Dangerous Type
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 7.2

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

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required High (PR:H)
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-2026-18933

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-2026-18933, 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-434: Unrestricted Upload of File with Dangerous Type, where the product allows the upload or transfer of dangerous file types that are automatically processed within its environment. 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

The wp-downloadmanager WordPress plugin, in version 1.68.11 (also affecting the 6.9.4 release line), allows an admin-privileged user (current_user_can('manage_downloads')) to upload arbitrary files via download-add.php with no extension or MIME-type validation of any kind - no wp_check_filetype_and_ext(), no validate_file(), and no extension blocklist exist anywhere in the upload handler. The destination path is additionally built by concatenating the raw, unsanitized $_POST['file_upload_to'] value with no traversal check (no ../ filtering, no basename()/realpath() applied). Since the base download path is required to live under WP_CONTENT_DIR (a web-accessible location), an uploaded PHP file lands in a web-servable path and can be directly executed, resulting in remote code execution. The plugin's own later changelog confirms these protections were absent in this version: v1.69 added file-type validation via wp_check_filetype_and_ext(), and v1.69.1 added directory-traversal protection - neither existed in 1.68.11.

References

NVD — CVE-2026-18933 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-18933
wordpress.org/plugins/wp-download... WEB
https://wordpress.org/plugins/wp-downloadmanager/#description

Frequently Asked Questions

What is CVE-2026-18933?
CVE-2026-18933 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-434: Unrestricted Upload of File with Dangerous Type.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-18933?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-18933?
CVE-2026-18933 has a CVSS v3.1 base score of 7.2 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-18933?
CVE-2026-18933 is classified under CWE-434: Unrestricted Upload of File with Dangerous Type (The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.).
How can I check Maven dependencies for CVE-2026-18933?
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-cc9f-29gq-5x7c",
  "modified" : "2026-08-05T12:31:33Z",
  "published" : "2026-08-05T12:31:33Z",
  "aliases" : [ "CVE-2026-18933" ],
  "details" : "The wp-downloadmanager WordPress plugin, in version 1.68.11 (also affecting the 6.9.4 release line), allows an admin-privileged user (current_user_can('manage_downloads')) to upload arbitrary files via download-add.php with no extension or MIME-type validation of any kind - no wp_check_filetype_and_ext(), no validate_file(), and no extension blocklist exist anywhere in the upload handler. The destination path is additionally built by concatenating the raw, unsanitized $_POST['file_upload_to'] value with no traversal check (no ../ filtering, no basename()/realpath() applied). Since the base download path is required to live under WP_CONTENT_DIR (a web-accessible location), an uploaded PHP file lands in a web-servable path and can be directly executed, resulting in remote code execution. The plugin's own later changelog confirms these protections were absent in this version: v1.69 added file-type validation via wp_check_filetype_and_ext(), and v1.69.1 added directory-traversal protection - neither existed in 1.68.11.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-18933"
  }, {
    "type" : "WEB",
    "url" : "https://wordpress.org/plugins/wp-downloadmanager/#description"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-434" ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-08-05T12:18:56Z"
  }
}