CVE-2026-109823 in Tidewave
Summary
by MITRE • 10/27/2026
An attacker can read the name of filesystem paths of your application present via Tidewave configuration via /tidewave/connect or via the rendered toolbar.
Neither response checks the Host header. A web page that rebinds its own domain to the loopback address can therefore read the tag with a same-origin request, which carries no Origin header. The paths usually reveal the local username and the project layout.
This issue affects tidewave: from 0.8.0 before 0.9.2.
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Analysis
by VulDB Data Team • 10/27/2026
The vulnerability identified in Tidewave versions prior to 0.9.2 represents a significant information disclosure flaw rooted in improper validation of HTTP request headers, specifically the Host header. This security lapse allows an attacker to access sensitive filesystem path names that are exposed through specific application endpoints or rendered interface components. The core technical failure lies in the absence of strict origin verification and host binding checks within the server-side logic handling requests directed at /tidewave/connect or similar toolbar-rendered interfaces. By neglecting to validate whether the incoming request originates from a trusted source or matches the expected domain, the application inadvertently permits cross-origin data retrieval under conditions that should typically be restricted by same-origin policies.
The operational mechanism of this exploit relies on DNS rebinding techniques combined with browser security model quirages regarding origin headers. An attacker can construct a malicious web page that dynamically rebinds its own registered domain to resolve as the loopback address, effectively pointing it toward the victim application running locally or within an internal network. When such a page makes a request to the vulnerable endpoint, the server processes the request without verifying the Host header against a whitelist of allowed domains. Crucially, this specific type of same-origin-like request does not carry an Origin header, which means standard browser-based cross-site request forgery protections and origin checks are bypassed entirely. This allows the attacker's script to successfully read the response content from within the context of the victim application as if it were a legitimate local interaction.
The impact of this vulnerability is primarily informational but can serve as a critical stepping stone for further attacks. The exposed data typically includes absolute filesystem paths, which often reveal the local username of the user running the application and the specific directory structure or project layout being used. While this does not directly grant code execution access, it provides an attacker with valuable reconnaissance data that aids in crafting more targeted exploits. Knowledge of file system structures can facilitate subsequent attacks such as path traversal attempts, configuration file reading if other vulnerabilities exist, or social engineering efforts based on the revealed user identity and project context. In environments where Tidewave is deployed for development or internal tooling, this exposure compromises the confidentiality of local environment details that are generally considered private to the running instance.
To mitigate this vulnerability, immediate updates to Tidewave version 0.9.2 or later are required as these versions address the underlying host validation logic. For systems where an upgrade is not immediately feasible, defensive measures should focus on network-level controls and application configuration hardening. Implementing strict firewall rules that restrict access to the affected endpoints from external networks can prevent remote exploitation via DNS rebinding. Additionally, configuring reverse proxies or web application firewalls to enforce strict Host header validation ensures that requests with mismatched or missing host identifiers are rejected before reaching the application logic. It is also advisable to disable unnecessary toolbar features and configuration endpoints in production environments where they are not strictly required, thereby reducing the attack surface available for information disclosure attacks.