chartbrew: Use of Default Cryptographic Key
CVE-2026-85295 is a critical-severity use of default cryptographic key vulnerability in chartbrew, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected chartbrew versions: < 5.2.3. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.4% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of chartbrew you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (github.com).
Official description
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, four authentication helpers accepted session tokens signed with CB_SECRET, including known, weak, or shipped-default values. The vulnerable surface is session JWT fallback in server/modules/verifyToken.js, verifyUser.js, getUserFromToken.js, and socketManager.js across the API and socket layer. A stock source or repository Docker Compose deployment retains a known, weak, or default CB_SECRET and an attacker submits a forged HS256 token decoding to a target user id. Knowing the symmetric secret lets the attacker create a token that the legacy verification fallback accepts as the target user without that user's password or two-factor authentication. The condition includes stock source and repository Docker Compose installs and any otherwise known or weak CB_SECRET; a bare container where CB_SECRET is undefined is not affected by this fallback path. A forged session impersonates the chosen user across the entire API and socket layer and exercises that user's Chartbrew privileges. This issue is fixed in version 5.2.3.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use of Default Cryptographic Key
The product uses a default cryptographic key for potentially critical functionality.
How developers prevent this class of flaw
- Prohibit use of default, hard-coded, or other values that do not vary for each installation of the product - especially for separate organizations.
- Force the administrator to change the credential upon installation.
- The product administrator could change the defaults upon installation or during operation.
More Use of Default Cryptographic Key vulnerabilities (CWE-1394)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other vulnerabilities in chartbrew
- 9.1 Critical severity
- 7.5 High severity
- 9.3 Critical severity
- 8.1 High severity
- 7.5 High severity
- 8.8 High severity
Recent Use of Default Cryptographic Key vulnerabilities
- 7.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 7.7 High severity
- 8.8 High severity
- 9.1 Critical severity
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