{
    "CVE_data_meta": {
        "ASSIGNER": "security-advisories@github.com",
        "ID": "CVE-2021-29509",
        "STATE": "PUBLIC",
        "TITLE": "Keepalive Connections Causing Denial Of Service in puma"
    },
    "affects": {
        "vendor": {
            "vendor_data": [
                {
                    "product": {
                        "product_data": [
                            {
                                "product_name": "puma",
                                "version": {
                                    "version_data": [
                                        {
                                            "version_value": "< 4.3.8"
                                        },
                                        {
                                            "version_value": ">= 5.0.0, < 5.3.1"
                                        }
                                    ]
                                }
                            }
                        ]
                    },
                    "vendor_name": "puma"
                }
            ]
        }
    },
    "data_format": "MITRE",
    "data_type": "CVE",
    "data_version": "4.0",
    "description": {
        "description_data": [
            {
                "lang": "eng",
                "value": "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."
            }
        ]
    },
    "impact": {
        "cvss": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
        }
    },
    "problemtype": {
        "problemtype_data": [
            {
                "description": [
                    {
                        "lang": "eng",
                        "value": "{\"CWE-400\":\"Uncontrolled Resource Consumption\"}"
                    }
                ]
            }
        ]
    },
    "references": {
        "reference_data": [
            {
                "name": "https://github.com/puma/puma/security/advisories/GHSA-q28m-8xjw-8vr5",
                "refsource": "CONFIRM",
                "url": "https://github.com/puma/puma/security/advisories/GHSA-q28m-8xjw-8vr5"
            },
            {
                "name": "https://gist.github.com/nateberkopec/4b3ea5676c0d70cbb37c82d54be25837",
                "refsource": "MISC",
                "url": "https://gist.github.com/nateberkopec/4b3ea5676c0d70cbb37c82d54be25837"
            },
            {
                "name": "https://github.com/puma/puma/security/policy",
                "refsource": "MISC",
                "url": "https://github.com/puma/puma/security/policy"
            },
            {
                "name": "https://rubygems.org/gems/puma",
                "refsource": "MISC",
                "url": "https://rubygems.org/gems/puma"
            },
            {
                "refsource": "GENTOO",
                "name": "GLSA-202208-28",
                "url": "https://security.gentoo.org/glsa/202208-28"
            },
            {
                "refsource": "MLIST",
                "name": "[debian-lts-announce] 20220827 [SECURITY] [DLA 3083-1] puma security update",
                "url": "https://lists.debian.org/debian-lts-announce/2022/08/msg00015.html"
            }
        ]
    },
    "source": {
        "advisory": "GHSA-q28m-8xjw-8vr5",
        "discovery": "UNKNOWN"
    }
}