CVE-2026-41247

Severity

High
bg can be injected into shell command construction, leading to possible RCE in affected configurations.

elFinder contains a command injection vulnerability in the resize command.

The bg (background color) parameter is accepted from user input and passed through image resize/rotate processing. In configurations that use the ImageMagick CLI backend, this value is incorporated into shell command strings without sufficient escaping. An attacker able to invoke the resize command with a crafted bg value may achieve arbitrary command execution as the web server process user.

This issue affects configurations where:

• the resize command is enabled,
• image processing uses the ImageMagick CLI backend, and
• the vulnerable code paths are reachable.

Affected versions

Affected: all versions before 2.1.66
Patched: 2.1.67

Details

The vulnerable flow is:

1. The resize command accepts the bg parameter from the request.
2. The parameter is passed into volume resize handling.
3. In ImageMagick CLI code paths, the value is interpolated into shell command strings.
4. Because the value is not safely constrained and escaped, shell metacharacters may be injected.

The issue was addressed by:

• validating bg against a strict allowlist of supported color formats, and
• safely escaping the value before it is passed into CLI command construction.

Workarounds

Possible mitigations for users who cannot upgrade immediately:

• disable the resize command if not required,
• avoid using the ImageMagick CLI backend for image processing,
• restrict access to trusted users only.

Upgrading to the patched release is strongly recommended.

Credits

Thanks to Lin, WeiChi and Drew Webber for the responsible disclosure.

An attacker may execute arbitrary OS commands with the privileges of the web server process.

Impact depends on server configuration, enabled commands, backend image library selection, and surrounding deployment controls.

Untrusted input reaches a shell command, allowing arbitrary commands to run on the host. Typical impact: code execution in the application's environment.

CVE-2026-41247 has a CVSS score of 9.8 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.1.67); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-41247? CVE-2026-41247 is a high-severity OS command injection vulnerability in studio-42/elfinder (composer), affecting versions < 2.1.67. It is fixed in 2.1.67. Untrusted input reaches a shell command, allowing arbitrary commands to run on the host.
2. How severe is CVE-2026-41247? CVE-2026-41247 has a CVSS score of 9.8 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of studio-42/elfinder are affected by CVE-2026-41247? studio-42/elfinder (composer) versions < 2.1.67 is affected.
4. Is there a fix for CVE-2026-41247? Yes. CVE-2026-41247 is fixed in 2.1.67. Upgrade to this version or later.
5. Is CVE-2026-41247 exploitable, and should I be worried? Whether CVE-2026-41247 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-41247 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-41247? Upgrade studio-42/elfinder to 2.1.67 or later.