{"id":"UBUNTU-CVE-2024-1135","details":"Gunicorn fails to properly validate Transfer-Encoding headers, leading to HTTP Request Smuggling (HRS) vulnerabilities. By crafting requests with conflicting Transfer-Encoding headers, attackers can bypass security restrictions and access restricted endpoints. This issue is due to Gunicorn's handling of Transfer-Encoding headers, where it incorrectly processes requests with multiple, conflicting Transfer-Encoding headers, treating them as chunked regardless of the final encoding specified. This vulnerability allows for a range of attacks including cache poisoning, session manipulation, and data exposure.","modified":"2026-05-20T16:08:43.691600675Z","published":"2024-04-16T00:15:00Z","upstream":["CVE-2024-1135"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2024-1135"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2024-1135"},{"type":"REPORT","url":"https://huntr.com/bounties/22158e34-cfd5-41ad-97e0-a780773d96c1"},{"type":"REPORT","url":"https://github.com/benoitc/gunicorn/commit/ac29c9b0a758d21f1e0fb3b3457239e523fa9f1d"}],"affected":[{"package":{"name":"gunicorn","ecosystem":"Ubuntu:Pro:14.04:LTS","purl":"pkg:deb/ubuntu/gunicorn?arch=source&distro=esm-infra-legacy%2Ftrusty"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["17.5-2","17.5-2build1","17.5-2ubuntu0.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"gunicorn","binary_version":"17.5-2ubuntu0.1~esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2024/UBUNTU-CVE-2024-1135.json"}},{"package":{"name":"gunicorn","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/gunicorn?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["19.0-8ubuntu1","19.4.1-1ubuntu1","19.4.5-1ubuntu1","19.4.5-1ubuntu1.1"],"ecosystem_specific":{"binaries":[{"binary_name":"gunicorn","binary_version":"19.4.5-1ubuntu1.1"},{"binary_version":"19.4.5-1ubuntu1.1","binary_name":"gunicorn-examples"},{"binary_name":"gunicorn3","binary_version":"19.4.5-1ubuntu1.1"},{"binary_name":"python-gunicorn","binary_version":"19.4.5-1ubuntu1.1"},{"binary_version":"19.4.5-1ubuntu1.1","binary_name":"python3-gunicorn"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2024/UBUNTU-CVE-2024-1135.json"}},{"package":{"name":"gunicorn","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/gunicorn?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["19.7.1-3","19.7.1-4"],"ecosystem_specific":{"binaries":[{"binary_version":"19.7.1-4","binary_name":"gunicorn"},{"binary_name":"gunicorn-examples","binary_version":"19.7.1-4"},{"binary_name":"gunicorn3","binary_version":"19.7.1-4"},{"binary_name":"python-gunicorn","binary_version":"19.7.1-4"},{"binary_version":"19.7.1-4","binary_name":"python3-gunicorn"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2024/UBUNTU-CVE-2024-1135.json"}},{"package":{"name":"gunicorn","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/gunicorn?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["19.9.0-1","19.9.0-4","20.0.0-1","20.0.2-1","20.0.4-1","20.0.4-2","20.0.4-3"],"ecosystem_specific":{"binaries":[{"binary_version":"20.0.4-3","binary_name":"gunicorn"},{"binary_name":"gunicorn-examples","binary_version":"20.0.4-3"},{"binary_version":"20.0.4-3","binary_name":"python3-gunicorn"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2024/UBUNTU-CVE-2024-1135.json"}},{"package":{"name":"gunicorn","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/gunicorn?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["20.1.0-1","20.1.0-2"],"ecosystem_specific":{"binaries":[{"binary_name":"gunicorn","binary_version":"20.1.0-2"},{"binary_name":"gunicorn-examples","binary_version":"20.1.0-2"},{"binary_name":"python3-gunicorn","binary_version":"20.1.0-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2024/UBUNTU-CVE-2024-1135.json"}},{"package":{"name":"gunicorn","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/gunicorn?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["20.1.0-6","20.1.0-6ubuntu0.1"],"ecosystem_specific":{"binaries":[{"binary_name":"gunicorn","binary_version":"20.1.0-6ubuntu0.1"},{"binary_version":"20.1.0-6ubuntu0.1","binary_name":"gunicorn-examples"},{"binary_name":"python3-gunicorn","binary_version":"20.1.0-6ubuntu0.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2024/UBUNTU-CVE-2024-1135.json"}},{"package":{"name":"gunicorn","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/gunicorn?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["23.0.0-1"],"ecosystem_specific":{"binaries":[{"binary_name":"gunicorn","binary_version":"23.0.0-1"},{"binary_version":"23.0.0-1","binary_name":"gunicorn-examples"},{"binary_name":"python3-gunicorn","binary_version":"23.0.0-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2024/UBUNTU-CVE-2024-1135.json"}},{"package":{"name":"gunicorn","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/gunicorn?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"intro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