First published: Fri Dec 17 2021(Updated: )
### Impact Users who deployed message bus with diagnostics features enabled (default off) were vulnerable to a path traversal bug, which could lead to disclosure of secret information on a machine if an unintended user were to gain access to the diagnostic route. The impact is also greater if there is no proxy for your web application as the number of steps up the directories is not bounded. For deployments which uses a proxy, the impact varies. For example, If a request goes through a proxy like Nginx with `merge_slashes` enabled, the number of steps up the directories that can be read is limited to 3 levels. ### Patches Patched in 3.3.7. ### Workarounds Disable MessageBus::Diagnostics in production like environments.
Credit: security-advisories@github.com security-advisories@github.com security-advisories@github.com
Affected Software | Affected Version | How to fix |
---|---|---|
rubygems/message_bus | <3.3.7 | 3.3.7 |
Discourse Message Bus | <3.3.7 | |
<3.3.7 |
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The severity of CVE-2021-43840 is classified as high due to the potential for secret information disclosure.
To address CVE-2021-43840, ensure that diagnostics features are disabled in the message bus configuration.
CVE-2021-43840 affects users of the message bus library version 3.3.7 and below when diagnostics features are enabled.
CVE-2021-43840 is a path traversal vulnerability that can lead to information disclosure.
The consequences of CVE-2021-43840 include the unauthorized access to sensitive information on the affected machine.