{"answers":{"affected":"3 open source packages ship an affected version, including waitress. It affects 1 product.","exploited":"There is no known exploitation of CVE-2020-5236 in the wild and no public exploit code.","fix":"Upgrade waitress to 1.4.3 or later.","what":"CVE-2020-5236 is a medium-severity denial of service vulnerability in Pylons Waitress, published on 4 Feb 2020. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link."},"fix_prompt":"Check this codebase for CVE-2020-5236 and fix it if it is affected.\n\nWhat it is: CVE-2020-5236 is a medium-severity denial of service vulnerability in Pylons Waitress, published on 4 Feb 2020. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.\nExploitation: There is no known exploitation of CVE-2020-5236 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- waitress (PyPI): affected all versions; fixed in 1.4.3\n- waitress (PyPI): affected from 1.4.2; fixed in 1.4.3\n- waitress (PyPI): affected from 1.4.2; fixed in 1.4.3\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-2020-5236/ (Markdown: https://insights.sbomify.com/CVE-2020-5236/index.md)","id":"CVE-2020-5236","markdown":"https://insights.sbomify.com/CVE-2020-5236/index.md","name":"CVE-2020-5236","record":{"aliases":["GHSA-73m2-3pwg-5fgc","PYSEC-2020-155"],"analysis":{"component_type":"server_software","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"Python WSGI server","requires_auth":"low_privilege","summary":"An attacker can cause a denial of service in Waitress by sending a request with an invalid header, triggering catastrophic regex backtracking and consuming all CPU resources.","user_interaction":"required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"waitress","vendor":"agendaless"}],"cvss":{"score":5.7,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[{"id":"CWE-400","name":"Uncontrolled Resource Consumption"}],"description":"Waitress version 1.4.2 allows a DOS attack When waitress receives a header that contains invalid characters. When a header like \"Bad-header: xxxxxxxxxxxxxxx\\x10\" is received, it will cause the regular expression engine to catastrophically backtrack causing the process to use 100% CPU time and blocking any other interactions. This allows an attacker to send a single request with an invalid header and take the service offline. This issue was introduced in version 1.4.2 when the regular expression was updated to attempt to match the behaviour required by errata associated with RFC7230. The regular expression that is used to validate incoming headers has been updated in version 1.4.3, it is recommended that people upgrade to the new version of Waitress as soon as possible.","ecosystems":["PyPI"],"exploits":{"exploitdb":0,"first_seen":"2020-02-06","github_poc":1,"max_poc_stars":3,"metasploit":0,"nuclei":0,"refs":[{"date":"2020-02-06T06:21:02Z","kind":"github_poc","ref":"https://github.com/motikan2010/CVE-2020-5236","stars":3,"title":"Waitress 1.4.2 ReDoS - CVE-2020-5236 (Blog Sample Code)"}],"tier":"poc_unverified"},"has_fix":true,"headline":"Catastrophic backtracking in regex allows Denial of Service in Waitress","id":"CVE-2020-5236","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"PyPI","product":null,"products":[],"type":"denial_of_service","year":"2020"},"n_packages":3,"n_references":2,"next":{"headline":"Relative Path Traversal in oneup/uploader-bundle","id":"CVE-2020-5237"},"packages":[{"ecosystem":"PyPI","fixed":["1.4.3"],"introduced":["0"],"last_affected":[],"package":"waitress","purl":"pkg:pypi/waitress","source":"PYSEC-2020-155"},{"ecosystem":"PyPI","fixed":["1.4.3"],"introduced":["1.4.2"],"last_affected":[],"package":"waitress","purl":null,"source":"GHSA-73m2-3pwg-5fgc"},{"ecosystem":"PyPI","fixed":["1.4.3"],"introduced":["1.4.2"],"last_affected":[],"package":"waitress","purl":"pkg:pypi/waitress","source":"GHSA-73m2-3pwg-5fgc"}],"prev":{"headline":"Out-of-memory condition in Nanopb is potentially exploitable","id":"CVE-2020-5235"},"products":["Waitress"],"published":"2020-02-04","related":[{"cvss_score":9.1,"headline":"Waitress has request processing race condition in HTTP pipelining with invalid first request","id":"CVE-2024-49768","kev_date_added":null,"published":"2024-10-29"},{"cvss_score":7.5,"headline":"Waitress has a denial of service leading to high CPU usage/resource exhaustion","id":"CVE-2024-49769","kev_date_added":null,"published":"2024-10-29"},{"cvss_score":7.5,"headline":"HTTP Request Smuggling in waitress","id":"CVE-2022-24761","kev_date_added":null,"published":"2022-03-17"},{"cvss_score":7.1,"headline":"HTTP Request Smuggling: Content-Length Sent Twice in Waitress","id":"CVE-2019-16792","kev_date_added":null,"published":"2020-01-22"},{"cvss_score":7.1,"headline":"HTTP Request Smuggling in Waitress: Invalid whitespace characters in headers","id":"CVE-2019-16789","kev_date_added":null,"published":"2019-12-26"},{"cvss_score":7.1,"headline":"HTTP Request Smuggling: LF vs CRLF handling in Waitress","id":"CVE-2019-16785","kev_date_added":null,"published":"2019-12-20"},{"cvss_score":7.1,"headline":"HTTP Request Smuggling: Invalid Transfer-Encoding in Waitress","id":"CVE-2019-16786","kev_date_added":null,"published":"2019-12-20"}],"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":"PyPA Advisory Database","prefix":"PYSEC"},{"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)"},{"class":"open","licence":"CC0","name":"PoC-in-GitHub"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2024-08-04","vendors":["Pylons"]},"summary":"An attacker can cause a denial of service in Waitress by sending a request with an invalid header, triggering catastrophic regex backtracking and consuming all CPU resources.","url":"https://insights.sbomify.com/CVE-2020-5236/"}