CVE-2026-44260: EFW4.X Authentication Bypass Vulnerability

CVE-2026-44260 Overview

CVE-2026-44260 is an authorization flaw in efw4.X, an Enterprise Framework for Web that integrates the elFinder file manager via a JSP tag. Versions prior to 4.08.010 fail to enforce the readonly flag server-side when the <efw:elFinder> tag is configured with protected=true. The elfinder_checkRisk routine validates that the client submits readonly=true matching the session value, but no event handler verifies that flag before performing write operations. An authenticated attacker who issues requests directly to the backend can perform arbitrary file operations even when the interface advertises read-only access. The issue is fixed in version 4.08.010.

Critical Impact
Authenticated attackers can bypass read-only enforcement to create, modify, or delete files on the server, breaking the confidentiality and integrity guarantees of protected elFinder instances.

Affected Products

efw4.X (Enterprise Framework for Web) versions prior to 4.08.010
Applications using the <efw:elFinder> JSP tag with protected=true
Deployments relying on the readonly flag for write protection

Discovery Timeline

2026-05-12 - CVE-2026-44260 published to NVD
2026-05-13 - Last updated in NVD database

Technical Details for CVE-2026-44260

Vulnerability Analysis

The vulnerability is an authorization weakness classified under [CWE-863] (Incorrect Authorization). The efw4.X framework exposes elFinder through a custom JSP tag intended to deliver a read-only file browser when protected=true is set. The intended control flow checks the session-bound readonly value against the client-submitted parameter inside elfinder_checkRisk. That check only confirms the client value is consistent, not that write operations should be denied.

Because no event handler downstream consults the readonly flag, every elFinder command handler proceeds with the requested operation. The flag instead controls only the rendered UI, disabling buttons, and the JSON response metadata fields write: 0 and locked: 1. Trusting the client to enforce restriction is the core design defect.

The attacker requires valid authentication, as reflected by the attack characteristics (network vector, low complexity, low privileges required). Successful exploitation yields high impact to confidentiality and integrity through unauthorized file reads, writes, and deletions.

Root Cause

The root cause is missing server-side authorization enforcement for write operations. The readonly state is validated for consistency between session and client but never consulted by command handlers such as upload, rm, mkdir, rename, or paste. Client-side UI cues and response metadata are treated as the security boundary, which can be trivially bypassed by crafting raw HTTP requests.

Attack Vector

An authenticated attacker sends elFinder command requests directly to the backend endpoint, bypassing the disabled UI controls. By submitting readonly=true to satisfy elfinder_checkRisk while invoking write commands, the attacker triggers file mutations on the server. No additional privileges, user interaction, or specialized tooling beyond an HTTP client are required. See the GitHub Security Advisory for the technical details published by the maintainers.

Detection Methods for CVE-2026-44260

Indicators of Compromise

Unexpected elFinder command requests such as cmd=rm, cmd=upload, cmd=mkdir, cmd=rename, or cmd=paste arriving at endpoints rendered by <efw:elFinder protected="true">
Server-side file system changes within elFinder-managed directories without corresponding administrative activity
Authenticated user sessions issuing write commands while their UI session was configured read-only

Detection Strategies

Inspect application access logs for elFinder POST requests carrying write cmd values against protected endpoints
Correlate session metadata (readonly=true) with the command parameter to identify policy-violating requests
Enable file integrity monitoring on directories exposed through elFinder to surface unauthorized changes

Monitoring Recommendations

Forward web application logs and file integrity events to a centralized SIEM for correlation across user sessions and file system mutations
Alert on any write-class elFinder command issued from sessions tagged as read-only
Track anomalous spikes in upload, delete, or rename operations originating from non-administrative accounts

How to Mitigate CVE-2026-44260

Immediate Actions Required

Upgrade efw4.X to version 4.08.010 or later where the authorization check is enforced server-side
Audit all JSP templates using <efw:elFinder protected="true"> and confirm they are running the patched version
Review file system audit logs for unauthorized writes since the protected configuration was deployed

Patch Information

The maintainers fixed this issue in efw4.X version 4.08.010. The patch adds server-side enforcement so that event handlers reject write operations when the session readonly value is true, rather than relying on UI-level controls. Refer to the GitHub Security Advisory GHSA-5454-qhrf-vcvh for release notes.

Workarounds

Restrict access to elFinder endpoints with a reverse proxy that blocks write-class cmd parameters until the upgrade is applied
Remove or disable <efw:elFinder> instances configured with protected=true if patching is not immediately possible
Apply file system permissions that prevent the application service account from writing to sensitive directories exposed through elFinder

bash

# Example reverse proxy rule (nginx) to block write commands
# pending upgrade to efw4.X 4.08.010
location /elfinder/connector {
    if ($arg_cmd ~* "^(rm|upload|mkdir|rename|paste|put|duplicate|archive|extract|resize)$") {
        return 403;
    }
    proxy_pass http://backend;
}