CVE-2021-29509
Published May 11, 2021
Last updated 2 years ago
Overview
- 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.
- Source
- security-advisories@github.com
- NVD status
- Analyzed
Social media
- Hype score
- Not currently trending
Risk scores
CVSS 3.1
- Type
- Primary
- Base score
- 7.5
- Impact score
- 3.6
- Exploitability score
- 3.9
- Vector string
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Severity
- HIGH
CVSS 2.0
- Type
- Primary
- Base score
- 5
- Impact score
- 2.9
- Exploitability score
- 10
- Vector string
- AV:N/AC:L/Au:N/C:N/I:N/A:P
Configurations
[
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:a:puma:puma:*:*:*:*:*:ruby:*:*",
"vulnerable": true,
"matchCriteriaId": "6615E4AB-9A83-493C-81D1-327943F967B1",
"versionEndExcluding": "4.3.8"
},
{
"criteria": "cpe:2.3:a:puma:puma:*:*:*:*:*:ruby:*:*",
"vulnerable": true,
"matchCriteriaId": "8C9744B0-7CD1-4B9A-ACE6-7A6199F24FD5",
"versionEndExcluding": "5.3.1",
"versionStartIncluding": "5.0.0"
}
],
"operator": "OR"
}
]
},
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "07B237A9-69A3-4A9C-9DA0-4E06BD37AE73"
}
],
"operator": "OR"
}
]
}
]