CVE-2025-31572 is a Cross-Site Request Forgery (CSRF) vulnerability identified in the v20202020 Multi Days Events and Multi Events in One Day Calendar plugin, affecting versions up to 1.1.3. CSRF vulnerabilities occur when an attacker tricks an authenticated user into submitting a forged request to a web application, causing the application to perform unintended actions on behalf of the user. In this case, the vulnerability allows attackers to manipulate calendar events without the user's consent by exploiting the lack of proper CSRF protections in the plugin. The affected plugin is used to manage multiple day events and multiple events within a single day, commonly integrated into content management systems or websites requiring event scheduling features. The vulnerability does not require the attacker to authenticate themselves, but it does require the victim to be logged in and visit a maliciously crafted webpage. Although no public exploits have been reported, the risk remains significant because successful exploitation can alter event data, potentially causing operational disruptions or misinformation. The absence of a CVSS score means the severity must be assessed based on impact and exploitability factors. The vulnerability primarily threatens the integrity and availability of calendar data, with moderate ease of exploitation and a limited scope confined to users of this specific plugin. The vendor has not yet released a patch, highlighting the need for immediate mitigation steps by administrators.

The primary impact of CVE-2025-31572 is unauthorized modification of calendar events, which can disrupt organizational workflows, event planning, and communication. Attackers can exploit this vulnerability to add, delete, or alter events, potentially causing confusion, missed meetings, or scheduling conflicts. This can affect business continuity, especially for organizations relying heavily on the calendar for coordination. While confidentiality is less impacted, the integrity and availability of calendar data are at risk. In environments where the calendar is integrated with other systems (e.g., notifications, resource booking), the impact could cascade, affecting broader operational processes. The ease of exploitation—requiring only that an authenticated user visits a malicious page—makes this a practical threat for attackers using phishing or social engineering techniques. Although no known exploits exist in the wild, the vulnerability could be leveraged in targeted attacks against organizations using this plugin. The scope is limited to websites using the affected plugin, but given the plugin's use in multiple countries and sectors, the overall risk is non-negligible.

1. Immediately implement anti-CSRF tokens in all forms and state-changing requests within the calendar plugin to ensure that requests originate from legitimate users. 2. Restrict calendar modification permissions to the minimum necessary user roles to reduce the attack surface. 3. Monitor logs for unusual calendar event changes or patterns that may indicate exploitation attempts. 4. Educate users about phishing and social engineering risks to reduce the likelihood of visiting malicious sites. 5. If possible, temporarily disable or restrict the plugin's event modification features until a vendor patch is available. 6. Regularly check for vendor updates or patches addressing this vulnerability and apply them promptly. 7. Employ web application firewalls (WAFs) with rules designed to detect and block CSRF attack patterns targeting the calendar plugin endpoints. 8. Conduct security reviews and penetration testing focused on CSRF and related web vulnerabilities in the affected environment. 9. Use Content Security Policy (CSP) headers to limit the ability of attackers to load malicious scripts or frames that could facilitate CSRF attacks.