CVE-2026-51852 in Agent-Zero
Summary
by MITRE • 10/01/2026
agent-zero 1.7, 1.8, 1.9, and 1.10 is vulnerable to Directory Traversal in python/helpers/file_browser.py:FileBrowser.save_file_b64. The save_file_b64 method accepts user-controlled file paths without normalization or validation, allowing path traversal attacks.
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Analysis
by VulDB Data Team • 10/01/2026
The vulnerability identified in agent-zero versions 1.7 through 1.10 represents a critical security flaw rooted in improper input handling within the Python helper module responsible for file system operations. Specifically, the function save_file_b64 located at python/helpers/file_browser.py fails to implement adequate sanitization or normalization of user-supplied file paths before utilizing them for write operations. This architectural oversight allows an attacker to manipulate the intended destination directory by injecting sequence characters that traverse up the directory hierarchy, a technique commonly known as Directory Traversal or Path Traversal. The core technical failure lies in the absence of robust validation mechanisms such as canonicalization checks, which would ensure that the resolved path remains within the designated safe boundaries defined by the application's security policy.
From an operational perspective, this flaw enables unauthorized access to sensitive files and directories outside the intended scope of the agent-zero environment. An attacker can exploit this weakness to write malicious scripts or configuration files into critical system locations, potentially leading to remote code execution if those files are subsequently executed by privileged processes. Alternatively, the vulnerability may be leveraged for data exfiltration by reading arbitrary files from the host operating system, thereby compromising confidentiality and integrity of stored information. The impact is particularly severe in environments where agent-zero operates with elevated privileges or has access to sensitive application data, as it effectively bypasses file isolation controls designed to contain the application's footprint.
This vulnerability aligns closely with CWE-22: Improper Limitation of a Pathname to a Restricted Directory, which categorizes flaws where software does not properly neutralize special elements within a pathname that can cause the path to resolve outside of the restricted directory. Furthermore, in the context of the MITRE ATT&CK framework, this exploit technique corresponds to T1083: File and Directory Discovery or potentially T1564: Hidden Files and Directories if used for persistence, depending on how the attacker utilizes the traversal capability. The lack of input validation is a fundamental deviation from secure coding practices that mandate strict adherence to allow-listing principles rather than relying on block-lists or implicit trust in user inputs.
To mitigate this vulnerability, developers must implement rigorous path normalization and validation logic within the save_file_b64 method. This involves resolving the absolute path of the intended file location and verifying that it resides strictly within an approved base directory using standard library functions such as os.path.realpath combined with startswith checks to prevent escape sequences from altering the destination. Additionally, implementing strict allow-listing for permitted characters in filenames can further reduce the attack surface by rejecting inputs containing dots or slashes unless explicitly required and validated. Upgrading to a patched version of agent-zero that addresses this input handling deficiency is essential for restoring security integrity. Organizations should also consider deploying runtime application self-protection mechanisms or file system monitoring tools to detect anomalous write operations originating from untrusted sources, providing an additional layer of defense against exploitation attempts.