CVE-2026-4809: Software Security Vulnerability Vulnerability

CRITICAL
Advisory Identifier: GHSA-2w6q-cfjg-6mjp
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CVSS 9.8
CWE-434
Published
Advisory Summary

CVE-2026-4809 is a CRITICAL (CVSS 9.8) 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-2026-4809 at a Glance

CVE Identifier CVE-2026-4809
GHSA Identifier GHSA-2w6q-cfjg-6mjp
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-434: Unrestricted Upload of File with Dangerous Type
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-2026-4809

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-2026-4809, 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

plank/laravel-mediable through version 6.4.0 can allow upload of a dangerous file type when an application using the package accepts or prefers a client-supplied MIME type during file upload handling. In that configuration, a remote attacker can submit a file containing executable PHP code while declaring a benign image MIME type, resulting in arbitrary file upload. If the uploaded file is stored in a web-accessible and executable location, this may lead to remote code execution. At the time of publication, no patch was available and the vendor had not responded to coordinated disclosure attempts.

References

NVD — CVE-2026-4809 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-4809
Software Source Repository REPOSITORY
https://github.com/plank/laravel-mediable
Software Release RELEASE
https://github.com/plank/laravel-mediable/releases/tag/6.4.0

Frequently Asked Questions

What is CVE-2026-4809?
CVE-2026-4809 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-2026-4809?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-4809?
CVE-2026-4809 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-2026-4809?
CVE-2026-4809 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-2026-4809?
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-2w6q-cfjg-6mjp",
  "modified" : "2026-03-26T12:30:29Z",
  "published" : "2026-03-26T12:30:29Z",
  "aliases" : [ "CVE-2026-4809" ],
  "details" : "plank/laravel-mediable through version 6.4.0 can allow upload of a dangerous file type when an application using the package accepts or prefers a client-supplied MIME type during file upload handling. In that configuration, a remote attacker can submit a file containing executable PHP code while declaring a benign image MIME type, resulting in arbitrary file upload. If the uploaded file is stored in a web-accessible and executable location, this may lead to remote code execution. At the time of publication, no patch was available and the vendor had not responded to coordinated disclosure attempts.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/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-2026-4809"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/plank/laravel-mediable"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/plank/laravel-mediable/releases/tag/6.4.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-434" ],
    "severity" : "CRITICAL",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-03-26T11:16:21Z"
  }
}