CVE Vulnerability

CVE-2021-43840

message_bus is a messaging bus for Ruby processes and web clients. In versions prior to 3.3.7 users who deployed message bus with diagnostics features enabled (default off) are 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. This issue has been patched in version 3.3.7. Users unable to upgrade should ensure that MessageBus::Diagnostics is disabled.

3.5 /10

CVSS v2.0 :

V3 Legend

Vector :

Exploitability : 6.8 / Impact : 2.9

Attack Vector

Attack Complexity

Privileges Required

User Interaction

Confidentiality Impact PARTIAL

Integrity Impact NONE

Availability Impact NONE

Scope

6.5 /10

CVSS v3.0 : MEDIUM

V3 Legend

Vector :

Exploitability : 2.8 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References
Link Resource
https://github.com/discourse/message_bus/security/advisories/GHSA-xmgj-5fh3-xjmm Third Party Advisory
https://github.com/discourse/message_bus/commit/9b6deee01ed474c7e9b5ff65a06bb0447b4db2ba Patch Third Party Advisory
Configurations

Configuration 1

cpe:2.3:a:discourse:message_bus:*:*:*:*:*:ruby:*:*
Information

Published : 2021-12-17 07:15

Updated : 2021-12-29 06:39

NVD link : CVE-2021-43840

Mitre link : CVE-2021-43840

Products Affected
No products.
CWE
CWE-22