CVE-2026-2947 identifies a cross-site scripting (XSS) vulnerability in the rymcu forest software, specifically in versions 0.0.1 through 0.0.5. The vulnerability resides in the updateUserInfo method of the UserInfoController.java file, which handles user profile updates. Due to improper input validation or sanitization, an attacker can inject malicious JavaScript code that executes in the context of other users' browsers. This type of vulnerability can lead to session hijacking, defacement, or redirection to malicious sites. The attack vector is remote and requires low privileges (PR:L), with some user interaction (UI:P) necessary to trigger the payload. The vulnerability does not require authentication (AT:N) and has no impact on availability (VA:N). The CVSS 4.0 vector indicates an exploitability rating of low complexity (AC:L) and no scope change (S:N). Although no active exploits are reported in the wild, a public exploit exists, increasing the urgency for mitigation. The vendor has not issued a patch or responded to disclosure, leaving users exposed. The lack of vendor response and patch availability means organizations must implement their own mitigations. The vulnerability affects Java-based web applications using the rymcu forest framework, which may be integrated into various enterprise or web-facing systems.

The primary impact of this vulnerability is on the confidentiality and integrity of user data within affected applications. Successful exploitation allows attackers to execute arbitrary scripts in users' browsers, potentially stealing session tokens, credentials, or performing actions on behalf of users. This can lead to account compromise, unauthorized data access, and reputational damage. Although availability is not directly affected, the indirect consequences of compromised accounts or defacement can disrupt business operations. The requirement for user interaction limits automated mass exploitation but targeted phishing or social engineering attacks could be effective. The presence of a public exploit increases the likelihood of opportunistic attacks. Organizations relying on rymcu forest for user profile management or other web services face increased risk, especially if they have not implemented additional input validation or security controls. The absence of vendor patches prolongs exposure and complicates remediation efforts.

Given the lack of official patches, organizations should implement immediate compensating controls. First, apply strict input validation and output encoding on all user-supplied data in the updateUserInfo function and related endpoints to prevent script injection. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in browsers. Monitor and log unusual user profile update activities to detect potential exploitation attempts. Educate users about phishing risks and encourage cautious interaction with unexpected links or inputs. If feasible, isolate or sandbox the affected component to limit exposure. Consider deploying Web Application Firewalls (WAFs) with rules targeting common XSS payloads to block malicious requests. Regularly review and update security configurations and prepare for patch deployment once the vendor releases a fix. Additionally, conduct security audits and penetration testing focused on input handling in the affected application areas.