CVE-2021-29509 in Puma

Resumen (Inglés)

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.

Responsable

GitHub, Inc.

Reservar

2021-03-30

Divulgación

2021-05-12

Voces

VulDB provides additional information and datapoints for this CVE:

ID	Vulnerabilidad	CWE	Exp	Con	CVE
174876	Puma Connection denegación de servicio	400	No está definido	Arreglo oficial	CVE-2021-29509