CVE-2022-27260

Vulnerability

ButterCMS v1.2.8 contains an arbitrary file upload vulnerability in its file upload component [1][2]. The application does not properly validate uploaded files, allowing an attacker to upload a specially crafted SVG file. Since SVGs can contain embedded scripts or be interpreted as XML, this can lead to arbitrary code execution. The vulnerable version is v1.2.8, as described in the CVE [2].

Exploitation

An attacker must have network access to the ButterCMS instance and the ability to reach the file upload feature (typically available to authenticated users). The attacker crafts a malicious SVG file containing embedded JavaScript or other executable content. By uploading this file through the upload component, the file is accepted without proper content-type or extension validation [2]. The attacker can then trigger the execution of the malicious code by accessing the uploaded file via its URL or through server-side processing.

Impact

Successful exploitation allows the attacker to execute arbitrary code on the server hosting ButterCMS [2]. This can lead to complete compromise of the application, including data exfiltration, installation of backdoors, or lateral movement within the network. The impact is high, as it affects confidentiality, integrity, and availability.

Mitigation

As of the publication date (2022-04-12), no official patch or fixed version for ButterCMS v1.2.8 has been released [1][2]. The vendor's GitHub repository does not mention a fix for this vulnerability [1]. Users should restrict access to the file upload feature, implement strict file validation (e.g., reject SVG files unless absolutely necessary), and monitor for any signs of exploitation. If possible, consider upgrading to a later version if a fix becomes available in the future.