CVE-2024-13550 is a path traversal vulnerability identified in the ABC Notation plugin for WordPress, developed by paulrosen. The flaw exists in all plugin versions up to and including 6.1.3 and is triggered via the 'file' attribute of the 'abcjs' shortcode. This attribute does not properly restrict pathname inputs, allowing authenticated users with Contributor-level permissions or higher to manipulate the file path and access arbitrary files on the server filesystem. The vulnerability leverages CWE-22, which involves improper limitation of a pathname to a restricted directory, enabling attackers to bypass intended directory restrictions. Exploitation requires no user interaction beyond authentication, and the attack vector is remote over the network. The vulnerability impacts confidentiality by exposing potentially sensitive server files but does not affect data integrity or availability. The CVSS 3.1 base score is 6.5, reflecting a medium severity level due to the requirement for authenticated access but ease of exploitation and high confidentiality impact. No public exploits have been reported yet, but the vulnerability poses a significant risk to WordPress sites using this plugin, especially those with multiple contributors. The lack of a patch at the time of reporting necessitates immediate mitigation efforts by administrators.

The primary impact of CVE-2024-13550 is unauthorized disclosure of sensitive information stored on the web server hosting the vulnerable WordPress site. Attackers with Contributor-level access can read arbitrary files, potentially including configuration files, database credentials, private keys, or other sensitive data. This can lead to further compromise of the website or backend systems if attackers leverage the disclosed information. The vulnerability does not allow modification or deletion of files, so integrity and availability impacts are minimal. However, the confidentiality breach can have severe consequences, including data leaks, privacy violations, and facilitation of subsequent attacks. Organizations relying on the ABC Notation plugin for content management or music notation display are at risk, particularly those with multiple authenticated contributors. The medium CVSS score reflects the balance between the requirement for authenticated access and the high impact on confidentiality. The absence of known exploits in the wild reduces immediate risk but does not eliminate the threat, especially as exploit code could be developed rapidly given the straightforward nature of path traversal attacks.

Until an official patch is released, organizations should implement several specific mitigations: 1) Restrict Contributor-level and higher permissions to trusted users only, minimizing the number of accounts that can exploit the vulnerability. 2) Disable or remove the ABC Notation plugin if it is not essential to reduce the attack surface. 3) Employ web application firewalls (WAFs) with custom rules to detect and block suspicious requests containing path traversal patterns in the 'file' parameter of the 'abcjs' shortcode. 4) Monitor server logs for unusual file access patterns or attempts to access sensitive files. 5) Isolate the WordPress environment with strict file system permissions to limit the files accessible by the web server user. 6) Prepare to apply vendor patches immediately once available and test updates in a staging environment before deployment. 7) Educate content contributors about the risk and enforce strong authentication policies to reduce account compromise likelihood. These targeted actions go beyond generic advice by focusing on the specific attack vector and user roles involved.