CVE-2025-3874 is a medium-severity vulnerability affecting the WordPress Simple Shopping Cart plugin developed by mra13, specifically all versions up to and including 5.1.3. The vulnerability is classified as CWE-639: Authorization Bypass Through User-Controlled Key, which is a form of Insecure Direct Object Reference (IDOR). The root cause lies in the plugin's failure to randomize a key that is controlled by the user, which is used to identify and access individual customer shopping carts. Because this key is predictable or guessable, unauthenticated attackers can exploit this flaw to access other users' shopping carts without authorization. This unauthorized access enables attackers to perform several malicious actions: viewing the contents of other customers' carts, editing product links within those carts, adding or deleting products, and even discovering coupon codes that may be stored or applied within the cart context. The vulnerability does not require any authentication or user interaction, and it can be exploited remotely over the network (AV:N). The attack complexity is low (AC:L), meaning that exploitation does not require special conditions or knowledge. The scope is unchanged (S:U), indicating that the vulnerability affects only the plugin and not other components of the system. The impact is limited to confidentiality and integrity (C:L/I:L), with no direct impact on availability (A:N). There are currently no known exploits in the wild, and no official patches or updates have been published at the time of this analysis. The vulnerability was publicly disclosed on May 1, 2025, and has been assigned a CVSS v3.1 base score of 6.5, reflecting a medium severity level. Given the widespread use of WordPress and the popularity of e-commerce plugins, this vulnerability poses a significant risk to online stores using this plugin, potentially leading to data leakage, unauthorized modification of shopping cart contents, and abuse of promotional mechanisms.

For European organizations, especially small to medium-sized enterprises (SMEs) and e-commerce businesses relying on WordPress with the Simple Shopping Cart plugin, this vulnerability can lead to unauthorized access to customer shopping data. This compromises customer privacy and trust, potentially violating GDPR requirements regarding personal data protection. Unauthorized modification of shopping carts can result in financial losses, either through manipulation of product orders or abuse of coupon codes. Additionally, the exposure of coupon codes can lead to revenue loss and fraud. Although the vulnerability does not directly affect system availability, the reputational damage and potential regulatory penalties could be substantial. Organizations in sectors with high e-commerce activity, such as retail, travel, and hospitality, are particularly at risk. Furthermore, attackers could use the information gained from this vulnerability as a foothold for further attacks, such as targeted phishing or fraud schemes. The lack of authentication and user interaction requirements lowers the barrier for exploitation, increasing the likelihood of attacks if the plugin remains unpatched.

1. Immediate mitigation involves disabling the Simple Shopping Cart plugin until a secure update is released. 2. Monitor official channels from the plugin developer (mra13) and WordPress for patches or updates addressing this vulnerability. 3. Implement web application firewall (WAF) rules to detect and block suspicious requests attempting to access or manipulate shopping cart keys, especially those that do not correspond to the authenticated user's session. 4. Conduct a thorough audit of all e-commerce plugins and their versions to identify vulnerable instances. 5. For organizations unable to disable the plugin immediately, consider restricting access to the shopping cart endpoints via IP whitelisting or rate limiting to reduce exposure. 6. Educate development and security teams about the risks of IDOR vulnerabilities and enforce secure coding practices, such as proper authorization checks and randomization of sensitive keys. 7. Review and enhance logging and monitoring to detect unusual activities related to shopping cart modifications or coupon code usage. 8. Prepare incident response plans to address potential exploitation scenarios, including customer notification and remediation steps in compliance with GDPR.