CVE-2021-29509

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.
Configurations

Configuration 1

cpe:2.3:a:puma:puma:*:*:*:*:*:ruby:*:*
cpe:2.3:a:puma:puma:*:*:*:*:*:ruby:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

Information

Published : 2021-05-11 05:15

Updated : 2022-10-27 12:39


NVD link : CVE-2021-29509

Mitre link : CVE-2021-29509

Products Affected
No products.
CWE