CVE-2026-81743 in Flowintel
Summary
by MITRE • 08/27/2026
Affected versions of Flowintel allow the LOG_FILE configuration value to be modified through system settings without restricting it to a filename inside the intended log directory.
Because the application constructs the log destination from this configurable value, an administrator could set LOG_FILE to an arbitrary filesystem path. Since attackers can influence logged content, this enables controlled data to be written into unintended files. The upstream commit specifically describes an exploitation chain in which an attacker injects a template into a chosen file and subsequently abuses application rendering behavior to execute code.
The patch removes LOG_FILE from the web-editable settings, introduces validate_log_file_name() to reject absolute paths, traversal, Windows paths, null bytes, and directory components, and centralizes log path construction through resolve_log_file_path().
Version impacted: >=3.3.0
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Analysis
by VulDB Data Team • 08/27/2026
The vulnerability identified in Flowintel versions 3.3.0 and above represents a critical insecure configuration management flaw that allows for arbitrary file write operations leading to remote code execution. This issue stems from the application's handling of the LOG_FILE configuration parameter, which is exposed through the web-based administrative interface without adequate validation or restriction mechanisms. In a secure architecture, log files should be confined to specific directories with restricted permissions to prevent tampering. However, in this vulnerable implementation, administrators can modify the LOG_FILE setting via system settings to point to any arbitrary path on the underlying filesystem. This lack of constraint transforms a standard logging mechanism into an attack vector for writing controlled data to unintended locations within the server environment.
The technical severity of this flaw is amplified by the application's rendering behavior. Once an attacker gains administrative access or exploits another vulnerability to modify the LOG_FILE setting, they can direct log output to files that are subsequently processed by the application’s template engine. By injecting malicious content into these logs through other input vectors such as user actions or system events, an attacker ensures that their crafted payload is written directly to a file under their control. When the application later renders this file using its templating logic, it interprets and executes the injected code. This specific exploitation chain leverages server-side template injection principles where untrusted data from log files is treated as executable template code rather than static text content.
From an industry standard perspective, this vulnerability aligns with CWE-94 Improper Control of Generation of Code (Code Injection) and CWE-200 Exposure of Sensitive Information to an Unauthorized Actor if the logs contain sensitive data prior to exploitation. The attack pattern corresponds closely to MITRE ATT&CK techniques involving Server-Side Request Forgery or Command and Control via file system interactions, specifically T1564 Hidden Files and Directories when used for persistence, though the primary impact here is immediate code execution through template rendering abuse. The root cause lies in CWE-20 Unrestricted Upload of File with Dangerous Type combined with CWE-73 External Control of File Name or Path, as the application fails to sanitize user-supplied configuration values that dictate file system operations.
The remediation strategy implemented by the upstream developers addresses these flaws through multiple layers of defense. First, the LOG_FILE parameter was removed from the web-editable settings entirely, preventing direct manipulation via the administrative interface and reducing the attack surface for privilege escalation or misconfiguration attacks. Second, a new validation function named validate_log_file_name() was introduced to enforce strict constraints on any log file path configuration. This validator rejects absolute paths, directory traversal sequences such as dot-dot-slash patterns, Windows-style path separators, null bytes which can truncate strings in some environments, and any attempt to specify subdirectories outside the intended logging root. Finally, all log path construction is centralized through a resolve_log_file_path() function that ensures consistency and prevents bypasses by enforcing canonicalization of paths before use.
For organizations running affected versions, immediate action is required to mitigate this risk. Upgrading to a patched version where LOG_FILE is no longer configurable via the web interface is the primary recommendation. If upgrading is not immediately feasible, administrators should manually restrict file system permissions on log directories and ensure that any existing configuration files do not contain absolute paths or traversal sequences in the logging settings. Additionally, implementing strict input validation for all administrative endpoints can help prevent similar misconfigurations from being applied through other vectors. Regular auditing of application configurations against security baselines is essential to detect such deviations before they are exploited by attackers seeking initial access or privilege escalation on compromised systems.