CVE-2021-29509
Puma Persistent Connection Resource Exhaustion Denial of Service
Description
Puma is a concurrent HTTP 1.1 server for Ruby/Rack applications. The fix for CVE-2019-16770 was incomplete. The original fix only protected existing connections that had already been accepted from having their requests starved by greedy persistent-connections saturating all threads in the same process. However, new connections may still be starved by greedy persistent-connections saturating all threads in all processes in the cluster. A `puma` server which received more concurrent `keep-alive` connections than the server had threads in its threadpool would service only a subset of connections, denying service to the unserved connections. This problem has been fixed in `puma` 4.3.8 and 5.3.1. Setting `queue_requests false` also fixes the issue. This is not advised when using `puma` without a reverse proxy, such as `nginx` or `apache`, because you will open yourself to slow client attacks (e.g. slowloris). The fix is very small and a git patch is available for those using unsupported versions of Puma.
INFO
Published Date :
May 11, 2021, 5:15 p.m.
Last Modified :
Oct. 27, 2022, 12:39 p.m.
Source :
[email protected]
Remotely Exploitable :
Yes !
Impact Score :
3.6
Exploitability Score :
3.9
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-2021-29509.
| URL | Resource |
|---|---|
| https://gist.github.com/nateberkopec/4b3ea5676c0d70cbb37c82d54be25837 | Patch Third Party Advisory |
| https://github.com/puma/puma/security/advisories/GHSA-q28m-8xjw-8vr5 | Patch Third Party Advisory |
| https://github.com/puma/puma/security/policy | Third Party Advisory |
| https://lists.debian.org/debian-lts-announce/2022/08/msg00015.html | Mailing List Third Party Advisory |
| https://rubygems.org/gems/puma | Product Third Party Advisory |
| https://security.gentoo.org/glsa/202208-28 | 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-2021-29509 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2021-29509 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.
-
CVE Modified by [email protected]
May. 14, 2024
Action Type Old Value New Value -
Modified Analysis by [email protected]
Oct. 27, 2022
Action Type Old Value New Value Changed Reference Type https://lists.debian.org/debian-lts-announce/2022/08/msg00015.html No Types Assigned https://lists.debian.org/debian-lts-announce/2022/08/msg00015.html Mailing List, Third Party Advisory Changed Reference Type https://security.gentoo.org/glsa/202208-28 No Types Assigned https://security.gentoo.org/glsa/202208-28 Third Party Advisory Added CWE NIST CWE-667 Added CPE Configuration OR *cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* -
CVE Modified by [email protected]
Aug. 27, 2022
Action Type Old Value New Value Added Reference https://lists.debian.org/debian-lts-announce/2022/08/msg00015.html [No Types Assigned] -
CVE Modified by [email protected]
Aug. 15, 2022
Action Type Old Value New Value Added Reference https://security.gentoo.org/glsa/202208-28 [No Types Assigned] -
Initial Analysis by [email protected]
May. 24, 2021
Action Type Old Value New Value Added CVSS V2 NIST (AV:N/AC:L/Au:N/C:N/I:N/A:P) Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Changed Reference Type https://gist.github.com/nateberkopec/4b3ea5676c0d70cbb37c82d54be25837 No Types Assigned https://gist.github.com/nateberkopec/4b3ea5676c0d70cbb37c82d54be25837 Patch, Third Party Advisory Changed Reference Type https://github.com/puma/puma/security/advisories/GHSA-q28m-8xjw-8vr5 No Types Assigned https://github.com/puma/puma/security/advisories/GHSA-q28m-8xjw-8vr5 Patch, Third Party Advisory Changed Reference Type https://github.com/puma/puma/security/policy No Types Assigned https://github.com/puma/puma/security/policy Third Party Advisory Changed Reference Type https://rubygems.org/gems/puma No Types Assigned https://rubygems.org/gems/puma Product, Third Party Advisory Added CPE Configuration OR *cpe:2.3:a:puma:puma:*:*:*:*:*:ruby:*:* versions up to (excluding) 4.3.8 *cpe:2.3:a:puma:puma:*:*:*:*:*:ruby:*:* versions from (including) 5.0.0 up to (excluding) 5.3.1
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2021-29509 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-2021-29509
weaknesses.
Exploit Prediction
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.
2.09 }} 0.12%
score
0.89358
percentile