Which versions of PHP are affected by CVE-2026-4591?

Organizations using A weakness should be aware of moderate risk from CVE-2026-4591, a OS command injection vulnerability rated CVSS 4.7.

Is there a public PoC exploit available for CVE-2026-4591?

Yes, a public proof-of-concept exploit is available for CVE-2026-4591. Prioritise patching immediately. EPSS: 0.2%.

How to fix or mitigate CVE-2026-4591?

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Validate input sanitization for user-controlled parameters.

PHP CVE-2026-4591

Q: What is the CVSS score of CVE-2026-4591?

CVE-2026-4591 has a CVSS 4.0 base score of 2.0 (Low). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/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. EPSS exploitation probability: 0.2%.

EUVD-2026-14457 LOW

OS Command Injection (CWE-78)

2026-03-23 VulDB

PHP Command Injection Kodbox Kalcaddle

2.0

CVSS 4.0 · NVD

Severity by source

NVD PRIMARY

2.0 LOW

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

High

User Interaction

None

Scope

Lifecycle Timeline

Severity Changed

Apr 29, 2026 - 01:11 NVD

MEDIUM LOW

CVSS changed

Apr 29, 2026 - 01:11 NVD

5.1 (MEDIUM) 2.0 (LOW)

CVSS changed

Apr 24, 2026 - 16:37 NVD

4.7 (MEDIUM) 5.1 (MEDIUM)

PoC Detected

Mar 24, 2026 - 15:54 vuln.today

Public exploit code

EUVD ID Assigned

Mar 23, 2026 - 15:45 euvd

EUVD-2026-14457

Analysis Generated

Mar 23, 2026 - 15:45 vuln.today

CVE Published

Mar 23, 2026 - 15:15 nvd

MEDIUM 4.7

DescriptionCVE.org

A weakness has been identified in kalcaddle kodbox 1.64. This affects the function checkBin of the file /workspace/source-code/plugins/fileThumb/app.php of the component fileThumb Endpoint. Executing a manipulation can lead to os command injection. The attack can be executed remotely. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.

AnalysisAI

The fileThumb endpoint in Kodbox 1.64 contains an OS command injection vulnerability in the checkBin function that allows authenticated remote attackers to execute arbitrary commands with the privileges of the web server process. Public exploit code exists for this vulnerability, and the vendor has not provided a patch despite early notification. An attacker with high-level privileges can leverage this to achieve remote code execution on affected systems.

Technical ContextAI

The vulnerability resides in the PHP-based Kodbox file management application (CPE: cpe:2.3:a:kalcaddle:kodbox:*:*:*:*:*:*:*:*), specifically in the /workspace/source-code/plugins/fileThumb/app.php file within the fileThumb component endpoint. The root cause is classified as CWE-78 (Improper Neutralization of Special Elements used in an OS Command), indicating that user-supplied input to the checkBin function is not properly sanitized before being passed to OS command execution functions. This is a classic command injection flaw where metacharacters or command separators in user input are interpreted as shell commands rather than literal data.

RemediationAI

The primary remediation is to upgrade Kodbox to a patched version greater than 1.64 once available; however, due to the vendor's lack of response, no official patch timeline exists. Immediate interim measures include: restricting network access to the fileThumb endpoint (/workspace/source-code/plugins/fileThumb/app.php) to trusted internal IP ranges via firewall or reverse proxy rules, limiting administrative user accounts to only those requiring access, and disabling the fileThumb plugin entirely if not actively used. Additionally, implement web application firewall (WAF) rules to detect and block command injection attempts targeting the checkBin function (e.g., detecting shell metacharacters like semicolons, pipes, backticks, and command substitution syntax in request parameters). Monitor access logs for suspicious patterns in the /plugins/fileThumb/ endpoint. For long-term security, consider migrating to actively maintained file management solutions or pressure the vendor (or community forks) for a security patch.