CVE-2026-102249: REBUILD Authorization Bypass Vulnerability

CVE-2026-102249 Overview

CVE-2026-102249 is a missing authorization vulnerability [CWE-862] affecting REBUILD versions up to 4.4.11. The flaw resides in the /commons/file-editor-save endpoint, where manipulation of the url or fileKey argument bypasses authorization checks. Remote attackers can exploit the weakness over the network without authentication or user interaction. Public exploit code has been released, and the vendor did not respond to disclosure attempts.

Critical Impact

Unauthenticated remote attackers can invoke the file editor save function to affect file resources referenced by the url and fileKey parameters, impacting confidentiality, integrity, and availability of managed content.

Affected Products

• REBUILD versions up to and including 4.4.11
• The /commons/file-editor-save endpoint component
• Deployments exposing REBUILD to untrusted networks

Discovery Timeline

• 2026-09-29 - CVE-2026-102249 published to the National Vulnerability Database
• 2026-09-29 - Last updated in NVD database

Technical Details for CVE-2026-102249

Vulnerability Analysis

The vulnerability affects the /commons/file-editor-save route in REBUILD. The endpoint accepts url and fileKey parameters that reference file resources, but the request handler does not enforce authorization before performing the save operation. As a result, an unauthenticated remote user can submit a crafted HTTP request and trigger the file editor save routine against arbitrary targeted resources.

Because the endpoint sits under /commons/, it is reachable without a session context. The absence of a permission check allows attackers to bypass the application's role model and interact with functionality intended for authorized users only.

Root Cause

The root cause is a missing authorization check [CWE-862] in the request handler for /commons/file-editor-save. The route validates neither the caller's identity nor the caller's rights on the object referenced by url or fileKey. Server-side access control was not applied to this action prior to executing the save logic.

Attack Vector

Exploitation requires only network access to the REBUILD web interface. An attacker sends an HTTP request to /commons/file-editor-save with attacker-supplied url and fileKey values. No credentials, tokens, or user interaction are required. Public exploit details are referenced in the GitHub Issue CVE-2026-26 and the VulDB entry for CVE-2026-102249.

The vulnerability mechanism is described in the referenced advisories; no synthetic exploit code is provided here. See the VulDB vulnerability record #411151 for additional context.

Detection Methods for CVE-2026-102249

Indicators of Compromise

• Unauthenticated HTTP POST or GET requests to /commons/file-editor-save in web server or reverse proxy logs
• Requests to /commons/file-editor-save containing unexpected url or fileKey parameter values referencing sensitive file resources
• Requests originating from external IP addresses with no preceding authenticated session cookie

Detection Strategies

• Alert on any access to /commons/file-editor-save that is not preceded by a successful authentication event for the same session
• Correlate requests to the endpoint with subsequent modification events on the referenced fileKey resources
• Baseline normal usage of the file editor endpoint and flag anomalous source addresses or user agents

Monitoring Recommendations

• Enable verbose access logging on the REBUILD application and forward logs to a central analytics platform
• Monitor web application firewall telemetry for requests matching the vulnerable URL pattern
• Track modification timestamps and integrity hashes for files exposed through the editor interface

How to Mitigate CVE-2026-102249

Immediate Actions Required

• Restrict network access to the REBUILD application to trusted networks or VPN-only reachability until a fix is available
• Block or rate-limit unauthenticated requests to /commons/file-editor-save at the reverse proxy or web application firewall layer
• Review access logs for prior requests to the affected endpoint and audit any modified files

Patch Information

No vendor patch has been published at the time of writing. The vendor was contacted about this disclosure and did not respond. Track the VulDB entry for CVE-2026-102249 and the upstream project for release announcements addressing REBUILD versions after 4.4.11.

Workarounds

• Deploy a reverse proxy rule that requires an authenticated session cookie before forwarding requests to /commons/file-editor-save
• Add a WAF signature that blocks requests to the endpoint containing external or unexpected url values
• Remove or disable the file editor feature if it is not required for business operations

# Example NGINX configuration to require authentication cookie for the vulnerable endpoint
location = /commons/file-editor-save {
    if ($cookie_JSESSIONID = "") {
        return 403;
    }
    proxy_pass http://rebuild_backend;
}