CVE-2025-28870 identifies a DOM-based Cross-site Scripting (XSS) vulnerability in the amoCRM WebForm component, versions up to and including 1.1. The vulnerability stems from improper neutralization of user-supplied input during the generation of web pages, which allows malicious scripts to be injected and executed within the victim's browser context. Unlike reflected or stored XSS, DOM-based XSS occurs entirely on the client side, exploiting unsafe handling of data in the Document Object Model. This flaw can be triggered when a user interacts with a specially crafted URL or web page that manipulates the WebForm's DOM elements without proper sanitization. The vulnerability does not require authentication, increasing the attack surface, and can lead to session hijacking, credential theft, or unauthorized actions performed on behalf of the user. Although no public exploits have been reported yet, the widespread use of amoCRM in customer relationship management and marketing automation makes this a significant concern. The lack of an available patch at the time of publication necessitates immediate attention to alternative mitigations. The vulnerability was reserved and published in March 2025, with no CVSS score assigned yet. The technical details confirm the issue is in versions up to 1.1, and the vulnerability is categorized under improper input neutralization during web page generation.

The impact of CVE-2025-28870 is substantial for organizations using amoCRM WebForm, as exploitation can lead to unauthorized script execution in users' browsers. This can compromise confidentiality by exposing sensitive customer data, including contact information and sales leads. Integrity may be affected if attackers manipulate form submissions or alter displayed content, potentially misleading users or corrupting data. Availability could be indirectly impacted if attackers leverage the vulnerability to perform actions that disrupt normal operations or cause denial of service through malicious scripts. Since amoCRM is a critical tool for sales and marketing teams, any compromise can disrupt business processes and damage customer trust. The vulnerability's ease of exploitation without authentication and the potential for phishing or social engineering attacks to lure users into triggering the XSS make it a high-risk threat. Organizations with large amoCRM deployments or those integrating WebForm into public-facing websites are particularly vulnerable. The absence of known exploits currently provides a window for proactive mitigation before active exploitation occurs.

To mitigate CVE-2025-28870, organizations should immediately monitor for updates and apply official patches from amocrm once available. In the interim, implement strict input validation and output encoding on all user-supplied data handled by the WebForm to prevent script injection. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of potential XSS attacks. Review and sanitize URLs and parameters used in WebForm integrations to avoid unsafe DOM manipulations. Educate users and administrators about the risks of clicking on suspicious links or interacting with untrusted content related to amoCRM forms. Consider deploying Web Application Firewalls (WAFs) with custom rules to detect and block XSS payloads targeting amoCRM WebForm endpoints. Conduct regular security assessments and penetration testing focused on client-side vulnerabilities. Finally, isolate amoCRM WebForm usage within secure network segments and limit exposure to only necessary users and systems to reduce attack surface.