CVE-2025-66297 is a vulnerability classified under CWE-1336, involving improper neutralization of special elements used in the Twig template engine within the Grav CMS platform. Grav is a file-based web platform widely used for content management. The flaw exists in versions prior to 1.8.0-beta.27, where an authenticated user with admin panel access and permissions to create or edit pages can enable Twig processing in the page frontmatter. By injecting malicious Twig expressions, the attacker can escalate privileges to full admin rights or execute arbitrary system commands through the scheduler API. This dual impact results in both privilege escalation and remote code execution capabilities. The vulnerability does not require user interaction beyond the initial authenticated access and can be exploited remotely over the network. The CVSS 4.0 base score of 7.4 reflects high severity due to network attack vector, low attack complexity, no need for additional privileges beyond limited admin panel access, and no user interaction. The vulnerability compromises confidentiality, integrity, and availability by allowing attackers to execute arbitrary commands and gain full control over the CMS environment. The issue is resolved in Grav version 1.8.0-beta.27, and users are strongly advised to upgrade. No public exploits have been reported yet, but the potential impact warrants immediate attention.

For European organizations, this vulnerability poses significant risks, especially for those relying on Grav CMS for web content management. Successful exploitation can lead to full administrative control over the CMS, enabling attackers to modify or delete content, inject malicious code, or pivot to other internal systems. This threatens data confidentiality and integrity, potentially leading to data breaches or defacement of websites. Remote code execution can also disrupt service availability, causing downtime and reputational damage. Organizations in sectors such as government, finance, healthcare, and media, which often use CMS platforms for public-facing websites, may face regulatory and compliance repercussions under GDPR if sensitive data is compromised. The ease of exploitation via network without additional user interaction increases the urgency for mitigation. Additionally, the scheduler API exposure means automated tasks could be hijacked to maintain persistence or launch further attacks.

European organizations should immediately upgrade Grav CMS installations to version 1.8.0-beta.27 or later to remediate this vulnerability. Until patching is possible, restrict admin panel access strictly to trusted personnel and implement strong authentication controls, including multi-factor authentication. Disable Twig processing in page frontmatter if not required, or enforce strict input validation and sanitization on any user-supplied content that could be processed by Twig. Monitor scheduler API usage for anomalous activity and restrict its access where feasible. Conduct regular audits of user permissions to ensure least privilege principles are maintained. Employ web application firewalls (WAFs) with custom rules to detect and block suspicious Twig expression patterns. Maintain comprehensive logging and alerting on admin panel and scheduler API interactions to enable rapid detection of exploitation attempts. Finally, educate administrators on the risks of enabling advanced template features without proper safeguards.