CVE-2024-6591 is a vulnerability classified under CWE-862 (Missing Authorization) found in the Ultimate WordPress Auction Plugin developed by nitesh_singh. The issue arises because the plugin's functions 'send_auction_email_callback' and 'resend_auction_email_callback' do not perform proper capability checks before sending emails. This omission allows unauthenticated attackers to invoke these functions remotely and send arbitrary emails to any recipient. The vulnerability affects all plugin versions up to and including 4.2.6. Exploiting this flaw does not require any privileges or user interaction, making it accessible to any remote attacker. The CVSS v3.1 base score is 5.8 (medium severity), reflecting the network attack vector, low attack complexity, no privileges required, no user interaction, and a scope change due to the ability to send emails on behalf of the vulnerable site. While confidentiality is not impacted, the integrity of email communications is compromised, enabling attackers to send potentially malicious or deceptive emails that could be used for phishing or social engineering. No patches or official fixes are currently linked, and no known exploits have been reported in the wild as of the publication date. However, the vulnerability's presence in a widely used WordPress plugin makes it a significant concern for website operators.

The primary impact of CVE-2024-6591 is the unauthorized ability to send emails from a compromised WordPress site using the Ultimate WordPress Auction Plugin. This can lead to phishing attacks, spam distribution, and reputational damage to the affected organization. Attackers can craft emails containing malicious links or attachments, potentially leading to further compromise of recipients' systems or credential theft. Since the vulnerability requires no authentication and no user interaction, it can be exploited at scale by automated tools. Organizations relying on this plugin may experience increased abuse of their email infrastructure, blacklisting of their domains, and loss of user trust. Additionally, the vulnerability could be leveraged as a stepping stone in more complex attack chains targeting customers or partners. The scope includes any WordPress site running the vulnerable plugin version, which could be substantial given WordPress's global market share and the plugin's usage. The lack of known exploits in the wild suggests limited active exploitation currently, but the risk remains high due to the ease of exploitation and potential impact.

To mitigate CVE-2024-6591, organizations should first verify if they are running the Ultimate WordPress Auction Plugin and identify the version in use. Since no official patch is currently linked, immediate mitigation steps include disabling or removing the plugin if it is not essential. If removal is not feasible, restrict access to the WordPress admin area and plugin endpoints using web application firewalls (WAFs) or IP whitelisting to prevent unauthenticated access to the vulnerable functions. Implement monitoring for unusual email sending activity originating from the website to detect exploitation attempts. Website administrators should also consider implementing outbound email filtering and rate limiting to reduce the impact of potential abuse. Regularly check for updates from the plugin developer or WordPress security advisories to apply patches once available. Additionally, educating users and recipients about phishing risks can help mitigate the impact of malicious emails sent via this vulnerability.