Chartbrew up to 5.2.2 Share Token Verification information disclosure

Summaryinfo

A vulnerability labeled as problematic has been found in Chartbrew up to 5.2.2. This affects an unknown part of the component Share Token Verification. Executing a manipulation can lead to information disclosure. This vulnerability appears as CVE-2026-85708. The attack may be performed from remote. There is no available exploit. The affected component should be upgraded.

Detailsinfo

A vulnerability has been found in Chartbrew up to 5.2.2 and classified as problematic. This vulnerability affects an unknown part of the component Share Token Verification. The manipulation with an unknown input leads to a information disclosure vulnerability. The CWE definition for the vulnerability is CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. As an impact it is known to affect confidentiality. CVE summarizes:

Chartbrew is an open-source web application that can connect directly to databases and APIs and use the data to create charts. Prior to 5.2.3, Chart share and embed tokens were signed with CB_SECRET, including known or shipped-default values in stock source and repository Docker Compose installs. The vulnerable surface is chart share-token verification and filter-access routes for private charts. An attacker who knows the deployment's CB_SECRET targets a private chart that has been shared at least once so a share-policy row exists, then forges a Chart-subject token for that chart id. The known signing key permits valid Chart tokens, and the filter-access path accepts sequential integer ids without requiring a legitimate share link; token expiry and revocation are ineffective once the secret is known. The condition requires a known or default secret and an existing share-policy row. A bare container where CB_SECRET is undefined is outside this path, and a unique secret excludes it only while the value remains unknown and unpredictable. An unauthenticated attacker can enumerate integer ids and read arbitrary private chart data, including chartData, without possessing a legitimate share link. This issue is fixed in version 5.2.3.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-85708 since 09/04/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1592.

Upgrading to version 5.2.3 eliminates this vulnerability.

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Productinfo

Name

• Chartbrew

Version

• 5.2.0
• 5.2.1
• 5.2.2

Website

• Product: https://github.com/chartbrew/chartbrew/

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