CVE-2026-97360 in HFS2
Summary
by MITRE • 09/24/2026
HFS2 version 2.4.0 and earlier contains an unauthenticated arbitrary file access vulnerability that allows unauthenticated attackers to read, write, append, and delete files anywhere the HFS service account has filesystem access outside the shared folder. Attackers can exploit the macro dispatcher's lack of authorization model combined with the path resolver's failure to confine absolute paths to manipulate the template engine and compromise the confidentiality, integrity, and availability of the host.
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Analysis
by VulDB Data Team • 09/24/2026
The vulnerability identified in HFS version 2.4.0 and earlier represents a critical security flaw rooted in fundamental architectural failures regarding access control and input validation. This unauthenticated arbitrary file access issue stems from two primary technical deficiencies: the macro dispatcher's complete lack of an authorization model and the path resolver's failure to properly confine absolute paths within designated boundaries. In typical web server architectures, user inputs are processed through a series of sanitization and permission checks before being executed or applied to filesystem operations. However, in this specific implementation, the system fails to verify whether the requesting entity has legitimate privileges to perform file manipulation tasks. This absence of an authorization layer means that any actor with network connectivity to the service can interact directly with internal processing mechanisms without providing credentials or undergoing identity verification.
The technical mechanism of exploitation relies on manipulating the template engine through crafted requests that leverage absolute paths. The path resolver, which is responsible for determining the location of files requested by users, does not enforce strict containment rules. Consequently, an attacker can supply file paths that escape the intended shared folder directory and target arbitrary locations on the host operating system where the HFS service account possesses permissions. By combining this path traversal capability with the macro dispatcher's ability to execute commands or load templates without restriction, attackers gain a powerful vector for interacting with the underlying filesystem. This allows them not only to read sensitive configuration files but also to write new content, append data to existing logs or scripts, and delete critical system files.
The operational impact of this vulnerability is severe, affecting all three pillars of information security: confidentiality, integrity, and availability. From a confidentiality standpoint, attackers can exfiltrate sensitive data stored outside the public-facing shared folder, including database credentials, private keys, and user-specific documents that were assumed to be secure due to their location on disk. The integrity impact is equally damaging, as the ability to write and append files allows adversaries to inject malicious code into web templates or system scripts, potentially leading to remote code execution if those modified files are subsequently processed by the server. Furthermore, the capability to delete arbitrary files can lead to a denial of service condition, rendering the HFS instance inoperable and disrupting any dependent services that rely on its availability.
This vulnerability aligns with CWE-284 Improper Access Control and CWE-22 Path Traversal: '..' Sequence, reflecting both the lack of authorization checks and the failure to validate file paths against a restricted directory structure. In terms of offensive security frameworks, this exploit maps directly to MITRE ATT&CK technique T1083 File and Directory Discovery for reconnaissance and T1564.002 Hidden Files and Directories if attackers use the vulnerability to conceal malicious artifacts. Additionally, the ability to write files relates to T1505.003 Web Shell: ASPX or similar web shell deployment techniques depending on the file types targeted.
Mitigation strategies must address both immediate remediation and long-term architectural improvements. The most effective solution is to upgrade HFS to a version where these vulnerabilities have been patched, ensuring that proper authorization checks are implemented in the macro dispatcher and strict path confinement is enforced by the resolver. In environments where upgrading is not immediately feasible, network-level controls such as firewalls should be configured to restrict access to the HFS service exclusively from trusted IP addresses, thereby reducing the attack surface for unauthenticated actors. Additionally, running the HFS service under a restricted user account with minimal filesystem permissions can limit the scope of damage an attacker could inflict even if they successfully exploit this vulnerability. Regular auditing of file system permissions and continuous monitoring for unusual file access patterns are also recommended to detect potential exploitation attempts early.