CVE-2026-72819 in Grav
Summary
by MITRE • 08/14/2026
Grav CMS before 2.0.13 contains a remote code execution vulnerability in the Flex Objects plugin settings validation that allows authenticated users to execute arbitrary code by uploading a ZIP file containing PHP code. Attackers can bypass routine name validation by using array notation instead of string notation, call the unZip routine with a malicious archive, and write PHP files to the web root for execution.
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Analysis
by VulDB Data Team • 08/14/2026
The vulnerability in Grav CMS prior to version 2.0.13 represents a critical remote code execution flaw within the Flex Objects plugin that fundamentally undermines the security posture of affected systems. This weakness stems from inadequate input validation mechanisms during file processing operations, specifically when handling ZIP archives containing PHP code. The flaw enables authenticated attackers with sufficient privileges to escalate their access and execute arbitrary commands on the target server, creating a severe pathway for system compromise.
The technical implementation of this vulnerability exploits a specific validation bypass technique involving array notation versus string notation manipulation. Attackers can circumvent standard filename validation routines by employing array-based input methods that are not properly sanitized or filtered during the upload process. This bypass mechanism allows malicious payloads to pass through security checks that would normally reject suspicious file types or content. The vulnerability specifically targets the unZip routine within the Flex Objects plugin, where the system processes uploaded archives without adequate verification of file contents or paths.
The operational impact of this vulnerability extends beyond simple code execution capabilities, as it provides attackers with persistent access to the affected web server infrastructure. When successful, the exploitation allows for the creation of PHP files directly in the web root directory, enabling immediate execution of malicious code without requiring additional attack vectors. This characteristic transforms what might otherwise be a limited privilege escalation into a full system compromise scenario. The vulnerability affects any environment running Grav CMS versions prior to 2.0.13 that have the Flex Objects plugin enabled and accessible to authenticated users.
Organizations impacted by this vulnerability should implement immediate mitigations including updating to Grav CMS version 2.0.13 or later, which contains proper input validation fixes for the Flex Objects plugin. Additionally, administrators should review and restrict access permissions for the Flex Objects plugin functionality, limiting its availability to only trusted users with legitimate administrative needs. Network-level protections such as web application firewalls can provide additional layers of defense by monitoring for suspicious file upload patterns and array-based input sequences that are characteristic of this exploitation technique. The vulnerability aligns with CWE-434 Unrestricted Upload of File with Dangerous Type and relates to ATT&CK techniques involving privilege escalation through web application vulnerabilities.
Security teams should conduct comprehensive audits of all Grav CMS installations to identify affected versions and ensure proper patching procedures are implemented across all environments. Regular security assessments should include validation of plugin configurations and monitoring for unauthorized modifications to the Flex Objects plugin settings. The remediation process requires careful attention to maintain system functionality while addressing the core validation weaknesses that enabled this attack vector. Organizations must also establish monitoring protocols to detect potential exploitation attempts, including unusual file upload activities and suspicious array-based input patterns in web server logs.