CVE-2026-18983: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-p2qh-mgvf-5q7f
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CVSS 7.5
CWE-434
Published
Advisory Summary

CVE-2026-18983 is a HIGH (CVSS 7.5) 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-2026-18983 at a Glance

CVE Identifier CVE-2026-18983
GHSA Identifier GHSA-p2qh-mgvf-5q7f
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-434: Unrestricted Upload of File with Dangerous Type
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 7.5

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

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
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-2026-18983

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-2026-18983, 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 One User Avatar | User Profile Picture plugin for WordPress is vulnerable to Stored Cross-Site Scripting in all versions up to, and including, 2.5.4 via the wpua_action_process_option_update function. This is due to insufficient file type validation in wp_handle_upload() called without a MIME allow-list, with post-write validation relying on the attacker-controlled client-supplied Content-Type header rather than a server-derived type, and no cleanup of files that fail the check. This makes it possible for authenticated attackers, with subscriber-level access and above, to upload files that may be executable, which makes remote code execution possible. in order to exploit this vulnerability an admin has to give subscribers permission to upload avatars. While PHP files and svg files are rejected, dxfp files are accepted.

References

NVD — CVE-2026-18983 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-18983
plugins.trac.wordpress.org/browser/one-user-av... WEB
https://plugins.trac.wordpress.org/browser/one-user-avatar/trunk/includes/class-wp-user-avatar.php#L45
plugins.trac.wordpress.org/browser/one-user-av... WEB
https://plugins.trac.wordpress.org/browser/one-user-avatar/trunk/includes/class-wp-user-avatar.php#L546
plugins.trac.wordpress.org/browser/one-user-av... WEB
https://plugins.trac.wordpress.org/browser/one-user-avatar/trunk/includes/class-wp-user-avatar.php#L549
plugins.trac.wordpress.org/changeset/3659509/o... WEB
https://plugins.trac.wordpress.org/changeset/3659509/one-user-avatar/trunk/includes/class-wp-user-avatar.php
plugins.trac.wordpress.org/changeset WEB
https://plugins.trac.wordpress.org/changeset?old_path=%2Fone-user-avatar/tags/2.5.4&new_path=%2Fone-user-avatar/tags/2.5.5
www.wordfence.com/threat-intel/vulner... WEB
https://www.wordfence.com/threat-intel/vulnerabilities/id/f413b610-839a-4a93-aec5-b6566371ccb7?source=cve

Frequently Asked Questions

What is CVE-2026-18983?
CVE-2026-18983 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-2026-18983?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-18983?
CVE-2026-18983 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-18983?
CVE-2026-18983 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-2026-18983?
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-p2qh-mgvf-5q7f",
  "modified" : "2026-08-28T06:31:04Z",
  "published" : "2026-08-28T06:31:04Z",
  "aliases" : [ "CVE-2026-18983" ],
  "details" : "The One User Avatar | User Profile Picture plugin for WordPress is vulnerable to Stored Cross-Site Scripting in all versions up to, and including, 2.5.4 via the wpua_action_process_option_update function. This is due to insufficient file type validation in wp_handle_upload() called without a MIME allow-list, with post-write validation relying on the attacker-controlled client-supplied Content-Type header rather than a server-derived type, and no cleanup of files that fail the check. This makes it possible for authenticated attackers, with subscriber-level access and above, to upload files that may be executable, which makes remote code execution possible. in order to exploit this vulnerability an admin has to give subscribers permission to upload avatars. While PHP files and svg files are rejected, dxfp files are accepted.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-18983"
  }, {
    "type" : "WEB",
    "url" : "https://plugins.trac.wordpress.org/browser/one-user-avatar/trunk/includes/class-wp-user-avatar.php#L45"
  }, {
    "type" : "WEB",
    "url" : "https://plugins.trac.wordpress.org/browser/one-user-avatar/trunk/includes/class-wp-user-avatar.php#L546"
  }, {
    "type" : "WEB",
    "url" : "https://plugins.trac.wordpress.org/browser/one-user-avatar/trunk/includes/class-wp-user-avatar.php#L549"
  }, {
    "type" : "WEB",
    "url" : "https://plugins.trac.wordpress.org/changeset/3659509/one-user-avatar/trunk/includes/class-wp-user-avatar.php"
  }, {
    "type" : "WEB",
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  }, {
    "type" : "WEB",
    "url" : "https://www.wordfence.com/threat-intel/vulnerabilities/id/f413b610-839a-4a93-aec5-b6566371ccb7?source=cve"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-434" ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-08-28T05:16:42Z"
  }
}