Critical

RCE in Xerte Online Toolkits elFinder connector via .php4 upload bypass

IdentifiersCVE-2026-34415CWE-184· Incomplete List of Disallowed Inputs

CVE-2026-34415 affects Xerte Online Toolkits 3.15 and earlier. The issue is an incomplete input validation flaw in the elFinder connector endpoint caused by an incorrect regular expression intended to block executable PHP file extensions. Because the filter fails to reject the .php4 extension, an attacker can upload malicious PHP content and rename it to use the .php4 suffix, which remains executable by the server. The provided context states that this weakness can be chained with authentication bypass and path traversal vulnerabilities, allowing an unauthenticated attacker to reach the vulnerable upload workflow and place executable payloads in a server-accessible location, resulting in arbitrary operating system command execution.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can result in unauthenticated remote code execution on the Xerte server. An attacker can execute arbitrary operating system commands with the privileges of the web server process, which can lead to full compromise of application data, modification or destruction of content, deployment of additional malware or webshells, credential theft, and potential lateral movement depending on host configuration and privileges. The supplied CVSS vectors indicate high impact to confidentiality, integrity, and availability.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, disable or restrict access to the elFinder connector endpoint, especially from untrusted networks. Prevent execution of uploaded files in writable directories at the web server and PHP handler level, including legacy PHP extensions such as .php4. Enforce strict allowlists for uploadable file types, store uploads outside the web root, and disable interpretation of script extensions in upload paths. In parallel, monitor for suspicious uploads, renamed files with PHP-related extensions, and unexpected command execution by the web server process.

Remediation

Patch, then assume compromise.

Upgrade Xerte Online Toolkits to a version newer than 3.15 that corrects the elFinder connector extension validation logic and addresses the related attack chain components referenced in the available fixes. Specifically, apply the vendor/project patches associated with the referenced commits and any release containing those changes. Validate that executable extensions including legacy PHP variants such as .php4 are explicitly blocked, that upload destinations cannot be manipulated via traversal, and that unauthenticated access to the connector is not possible.

PUBLIC EXPLOITS

Exploits

No valid public exploits. Mallory filtered out 1 candidate as fakes, detection scripts, or README-only repos.

VALID 0 / 1 TOTALView more in app

All candidate exploits were filtered out by Mallory's validation.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

XerteOnline Toolkitsapplication

XerteXerte Online Toolkitsapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

5 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

5 SOURCESView more in app

cvefeed high severityNews

Apr 22, 2026

CVE-2026-34415 - Xerte Online Toolkits File Upload RCE via elfinder Connector

A remote code execution vulnerability in Xerte Online Toolkits 3.15 and earlier caused by incomplete input validation in the elFinder connector endpoint, allowing upload and execution of malicious PHP code via the .php4 extension when combined with authentication bypass and path traversal issues.

What this page doesn’t show

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Exposure mapping

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Threat actor evidence

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Associated malware

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Detection signatures

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Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity4