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Debian: CVE-2021-29509: puma -- security update

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Debian: CVE-2021-29509: puma -- security update

Severity
5
CVSS
(AV:N/AC:L/Au:N/C:N/I:N/A:P)
Published
05/11/2021
Created
08/29/2022
Added
08/29/2022
Modified
08/29/2022

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.

Solution(s)

  • debian-upgrade-puma

References

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