Keepalive Connections Causing Denial Of Service in puma
This vulnerability is related to CVE-2019-16770.
Impact
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.
Patches
This problem has been fixed in puma 4.3.8 and 5.3.1.
Workarounds
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).
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Bumps puma from 4.3.5 to 4.3.8. This update includes a security fix.
Vulnerabilities fixed
Sourced from The GitHub Security Advisory Database.
... (truncated)
Release notes
Sourced from puma's releases.
Changelog
Sourced from puma's changelog.
Commits
b911c134.3.8 release note09bb777Bump version constant8088950Close keepalive connections after MAX_FAST_INLINE requestsf3c95af4.3.777a90ecBackport set CONTENT_LENGTH for chunked requests (#2496)a418e5cUpdates to 4.3.6 to pass CI, adds Ubuntu 20.04 [changelog skip] (#2380)3e3647av4.3.673cfdf5Merge pull request #2314 from venables/fix-includefa54f4dMerge pull request #2269 from MSP-Greg/json-requireDependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting
@dependabot rebase.Dependabot commands and options
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