CVE-2021-43840
Message Bus Path Traversal Vulnerability
Description
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.
INFO
Published Date :
Dec. 17, 2021, 7:15 p.m.
Last Modified :
Dec. 29, 2021, 6:39 p.m.
Source :
[email protected]
Remotely Exploitable :
Yes !
Impact Score :
3.6
Exploitability Score :
2.8
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2021-43840.
| URL | Resource |
|---|---|
| https://github.com/discourse/message_bus/commit/9b6deee01ed474c7e9b5ff65a06bb0447b4db2ba | Patch Third Party Advisory |
| https://github.com/discourse/message_bus/security/advisories/GHSA-xmgj-5fh3-xjmm | Third Party Advisory |
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2021-43840 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2021-43840 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by [email protected]
May. 14, 2024
Action Type Old Value New Value -
Initial Analysis by [email protected]
Dec. 29, 2021
Action Type Old Value New Value Added CVSS V2 NIST (AV:N/AC:M/Au:S/C:P/I:N/A:N) Added CVSS V3.1 NIST AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N Changed Reference Type https://github.com/discourse/message_bus/commit/9b6deee01ed474c7e9b5ff65a06bb0447b4db2ba No Types Assigned https://github.com/discourse/message_bus/commit/9b6deee01ed474c7e9b5ff65a06bb0447b4db2ba Patch, Third Party Advisory Changed Reference Type https://github.com/discourse/message_bus/security/advisories/GHSA-xmgj-5fh3-xjmm No Types Assigned https://github.com/discourse/message_bus/security/advisories/GHSA-xmgj-5fh3-xjmm Third Party Advisory Added CPE Configuration OR *cpe:2.3:a:discourse:message_bus:*:*:*:*:*:ruby:*:* versions up to (excluding) 3.3.7
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2021-43840 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2021-43840
weaknesses.
Exploit Prediction
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.
0.07 }} -0.00%
score
0.29089
percentile