CVE-2026-76083 in Redash
Summary
by MITRE • 10/14/2026
Redash is a package for data visualization and sharing. From 10.0.0 until 26.9.0, the JSON data source query runner in redash/query_runner/json_ds.py used _get_all_results() to combine its configured base_url with a user-supplied query URL by using urljoin. An absolute query URL replaced the configured base URL instead of remaining under it, allowing a user with execute_query permission to direct a server-side request to an arbitrary external origin. When HTTP Basic Auth was configured for the data source, the request also forwarded those credentials to the selected origin. Private and internal address access remained constrained when REDASH_ENFORCE_PRIVATE_IP_BLOCK was enabled. This issue is fixed in version 26.9.0.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability identified within Redash versions ranging from 10.0.0 through 26.9.0 represents a critical server-side request forgery flaw rooted in the improper handling of URL construction for JSON data sources. The core technical deficiency lies in the implementation of the _get_all_results function located in the redash/query_runner/json_ds.py module, which utilizes Python's urllib.parse.urljoin method to concatenate a configured base_url with a user-supplied query URL. This approach fails to enforce strict path containment because urljoin behaves according to standard URI resolution rules where an absolute path or scheme in the second argument completely replaces the corresponding components of the first argument rather than appending to it. Consequently, if a malicious actor provides a fully qualified domain name as part of their query input, the resulting request is directed away from the intended internal data source and toward an arbitrary external origin controlled by the attacker.
This behavior creates a significant security risk for organizations utilizing Redash with HTTP Basic Authentication enabled on their JSON data sources. When such authentication credentials are configured at the system level to secure access to legitimate backend services, the vulnerability allows these sensitive credentials to be inadvertently forwarded to the maliciously specified external endpoint. This exposure compromises the confidentiality of internal secrets and potentially enables further attacks against downstream systems if those credentials hold broader privileges than intended for the specific data source context. The impact is particularly severe in environments where Redash serves as a central hub for business intelligence, as it effectively bypasses network-level controls that might otherwise restrict outbound traffic to known safe domains.
The operational impact of this vulnerability extends beyond simple credential leakage. It facilitates unauthorized access to internal resources if the attacker can manipulate the request into targeting an internal IP address or hostname through specific URL formatting tricks, although Redash includes a mitigation feature called REDASH_ENFORCE_PRIVATE_IP_BLOCK that restricts private and internal address access when enabled. This configuration option acts as a crucial defense-in-depth measure by validating destination IPs against known private ranges before the request is dispatched. However, reliance on this single control is insufficient because it does not prevent requests to public but maliciously controlled domains where credentials are still exfiltrated. The presence of execute_query permission in Redash grants users the ability to trigger these data source interactions, meaning any authenticated user with basic query execution rights can exploit this flaw without requiring administrative privileges.
From a classification perspective, this vulnerability aligns with CWE-918 Server-Side Request Forgery (SSRF), specifically involving improper validation of URL inputs that leads to unauthorized outbound connections. It also maps to MITRE ATT&CK technique T1534 Internal Spearphishing or potentially T1071 Application Layer Protocol if used for data exfiltration, as the attacker leverages legitimate application functionality to communicate with external infrastructure while carrying valid authentication tokens. The flaw highlights a common pitfall in web development where developers assume that joining URLs will always result in paths remaining under a base directory, ignoring the semantic differences between relative and absolute path resolution defined by RFC 3986.
To mitigate this risk, organizations must upgrade to Redash version 26.9.0 or later, which implements corrected logic for URL construction that ensures user-supplied inputs are strictly treated as relative paths appended to the base URL rather than independent URIs capable of overriding the host component. In environments where upgrading is not immediately feasible, administrators should ensure that REDASH_ENFORCE_PRIVATE_IP_BLOCK is enabled and rigorously configured to block all private IP ranges. Additionally, implementing network-level egress filtering via firewalls or proxy servers can restrict outbound connections from Redash hosts to only those domains explicitly required for business operations, thereby limiting the attack surface even if application-layer controls are bypassed. Regular audits of data source configurations should also be conducted to minimize the number of sources that require HTTP Basic Auth, reducing the value of stolen credentials in case of future vulnerabilities.