{"answers":{"affected":"4 open source packages ship an affected version, including puma. It affects 2 products.","exploited":"There is no known exploitation of CVE-2021-29509 in the wild and no public exploit code.","fix":"Upgrade puma to a fixed version for your release line: 4.3.8 or 5.3.1.","what":"CVE-2021-29509 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 11 May 2021. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2021-29509 and fix it if it is affected.\n\nWhat it is: CVE-2021-29509 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 11 May 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2021-29509 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- puma (RubyGems): affected all versions; fixed in 4.3.8\n- puma (RubyGems): affected all versions; fixed in 4.3.8\n- puma (RubyGems): affected from 5.0.0; fixed in 5.3.1\n- puma (RubyGems): affected from 5.0.0; fixed in 5.3.1\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2021-29509/ (Markdown: https://insights.sbomify.com/CVE-2021-29509/index.md)","id":"CVE-2021-29509","markdown":"https://insights.sbomify.com/CVE-2021-29509/index.md","name":"CVE-2021-29509","record":{"aliases":["DEBIAN-CVE-2021-29509","GHSA-q28m-8xjw-8vr5","OESA-2021-1203","SUSE-SU-2021:2761-1","SUSE-SU-2021:2914-1"],"analysis":{"component_type":"server_software","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"Ruby HTTP server","requires_auth":"none","summary":"An attacker can exhaust server threads with keep-alive connections, denying service to legitimate users in Puma HTTP server.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"debian_linux","vendor":"debian"},{"product":"puma","vendor":"puma"}],"cvss":{"score":7.5,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[{"id":"CWE-667","name":"Improper Locking"},{"id":"CWE-400","name":"Uncontrolled Resource Consumption"}],"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.","ecosystems":["RubyGems","SUSE:OpenStack Cloud Crowbar 8","SUSE:OpenStack Cloud Crowbar 9"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"Keepalive Connections Causing Denial Of Service in puma","id":"CVE-2021-29509","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"RubyGems","product":"debian:debian_linux","products":["debian:debian_linux"],"type":"denial_of_service","year":"2021"},"n_packages":6,"n_references":6,"next":{"headline":"Use of \"infinity\" as an input to datetime and date fields causes infinite loop in pydantic","id":"CVE-2021-29510"},"packages":[{"ecosystem":"RubyGems","fixed":["4.3.8"],"introduced":["0"],"last_affected":[],"package":"puma","purl":null,"source":"GHSA-q28m-8xjw-8vr5"},{"ecosystem":"RubyGems","fixed":["4.3.8"],"introduced":["0"],"last_affected":[],"package":"puma","purl":"pkg:gem/puma","source":"GHSA-q28m-8xjw-8vr5"},{"ecosystem":"RubyGems","fixed":["5.3.1"],"introduced":["5.0.0"],"last_affected":[],"package":"puma","purl":null,"source":"GHSA-q28m-8xjw-8vr5"},{"ecosystem":"RubyGems","fixed":["5.3.1"],"introduced":["5.0.0"],"last_affected":[],"package":"puma","purl":"pkg:gem/puma","source":"GHSA-q28m-8xjw-8vr5"},{"ecosystem":"SUSE:OpenStack Cloud Crowbar 8","fixed":["2.16.0-3.12.1"],"introduced":["0"],"last_affected":[],"package":"rubygem-puma","purl":"pkg:rpm/suse/rubygem-puma\u0026distro=SUSE%20OpenStack%20Cloud%20Crowbar%208","source":"SUSE-SU-2021:2761-1"},{"ecosystem":"SUSE:OpenStack Cloud Crowbar 9","fixed":["2.16.0-4.12.1"],"introduced":["0"],"last_affected":[],"package":"rubygem-puma","purl":"pkg:rpm/suse/rubygem-puma\u0026distro=SUSE%20OpenStack%20Cloud%20Crowbar%209","source":"SUSE-SU-2021:2914-1"}],"prev":{"headline":"Insecure deserialization in Wire","id":"CVE-2021-29508"},"products":["puma"],"published":"2021-05-11","related":[{"cvss_score":10,"headline":"ProFTPD Improper Access Control","id":"CVE-2015-3306","kev_date_added":"2026-10-08","published":"2015-05-18"},{"cvss_score":9.9,"headline":"RoundCube Webmail Deserialization of Untrusted Data","id":"CVE-2025-49113","kev_date_added":"2026-02-20","published":"2025-06-02"},{"cvss_score":9.8,"headline":"GNU InetUtils Argument Injection","id":"CVE-2026-24061","kev_date_added":"2026-01-26","published":"2026-01-21"},{"cvss_score":9.8,"headline":"Linux Kernel Improper Check for Unusual or Exceptional Conditions","id":"CVE-2025-39682","kev_date_added":"2026-09-18","published":"2025-09-05"},{"cvss_score":9.8,"headline":"Mozilla Firefox Use-After-Free","id":"CVE-2024-9680","kev_date_added":"2024-10-15","published":"2024-10-09"},{"cvss_score":9.8,"headline":"RARLAB UnRAR Directory Traversal","id":"CVE-2022-30333","kev_date_added":"2022-08-09","published":"2022-05-09"},{"cvss_score":9.8,"headline":"Roundcube Webmail SQL Injection","id":"CVE-2021-44026","kev_date_added":"2023-06-22","published":"2021-11-19"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"CC BY 4.0","name":"SUSE","prefix":"SUSE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2024-08-03","vendors":["puma"]},"summary":"An attacker can exhaust server threads with keep-alive connections, denying service to legitimate users in Puma HTTP server.","url":"https://insights.sbomify.com/CVE-2021-29509/"}