CVE-2023-30186 in Document Server
Summary
by MITRE • 08/14/2023
A use after free issue discovered in ONLYOFFICE DocumentServer 4.0.3 through 7.3.2 allows remote attackers to run arbitrary code via crafted JavaScript file.
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Analysis
by VulDB Data Team • 07/10/2026
The vulnerability CVE-2023-30186 represents a critical use-after-free flaw in ONLYOFFICE DocumentServer versions ranging from 4.0.3 to 7.3.2. This security defect arises from improper memory management within the document processing engine that handles JavaScript file execution. The flaw manifests when the application processes specially crafted JavaScript files that trigger a scenario where freed memory blocks are accessed after being deallocated, creating a dangerous condition that can be exploited by remote attackers. Such vulnerabilities typically occur in environments where dynamic memory allocation and deallocation processes are not properly synchronized with subsequent memory access patterns.
The technical exploitation of this use-after-free vulnerability follows a specific attack pattern that aligns with CWE-416, which categorizes improper free conditions in memory management. Attackers can craft malicious JavaScript files that, when processed by the vulnerable DocumentServer, cause the application to free memory resources while still maintaining references to them. This creates a situation where subsequent operations on the freed memory can result in arbitrary code execution, allowing attackers to gain unauthorized control over the affected system. The vulnerability is particularly concerning because it enables remote code execution without requiring authentication, making it highly attractive to threat actors seeking to compromise systems running vulnerable versions of ONLYOFFICE DocumentServer.
The operational impact of this vulnerability extends beyond simple code execution, as it can lead to complete system compromise and data exfiltration. Organizations relying on ONLYOFFICE DocumentServer for document processing and collaboration may face unauthorized access to sensitive documents, potential lateral movement within network infrastructure, and disruption of business operations. The remote nature of the exploit means that attackers can target vulnerable systems from anywhere on the internet without requiring physical access or network proximity. This vulnerability directly relates to ATT&CK technique T1059.007 for JavaScript and T1059.001 for command and scripting interpreter, as it leverages JavaScript processing capabilities to execute malicious payloads. The attack surface is particularly broad given that ONLYOFFICE DocumentServer is commonly used in enterprise environments for document collaboration, making it a prime target for sophisticated cyber attacks.
Mitigation strategies for CVE-2023-30186 should prioritize immediate patching of all affected versions to the latest stable releases that contain memory management fixes. Organizations should implement network segmentation to limit access to DocumentServer instances and deploy intrusion detection systems to monitor for suspicious JavaScript file processing activities. Additionally, administrators should consider implementing strict file validation and sanitization protocols to prevent the processing of untrusted JavaScript content. The vulnerability demonstrates the importance of proper memory management practices in web applications and highlights the need for comprehensive security testing of document processing engines. Organizations should also conduct regular security assessments of their document management systems and maintain up-to-date threat intelligence to identify potential exploitation attempts. The remediation process should include thorough testing of patched environments to ensure that the memory management fixes do not introduce regressions in document processing functionality.