{"cve":"CVE-2024-1135","nvd":{"published":"2024-04-16T00:15:07.797","modified":"2026-06-17T07:03:32.610","status":"Deferred","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.0","vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","score":7.5},"cwes":["CWE-444"],"references":["https://huntr.com/bounties/22158e34-cfd5-41ad-97e0-a780773d96c1","https://lists.debian.org/debian-lts-announce/2024/06/msg00027.html","https://huntr.com/bounties/22158e34-cfd5-41ad-97e0-a780773d96c1","https://lists.debian.org/debian-lts-announce/2024/06/msg00027.html","https://lists.debian.org/debian-lts-announce/2024/12/msg00018.html"],"products":[],"source":"nvd","synced_at":"2026-10-19T21:48:32.179249784+00:00"},"epss":{"cve":"CVE-2024-1135","score":0.02996,"percentile":0.87346,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-w3h3-4rj7-4ph4","url":"https://osv.dev/vulnerability/GHSA-w3h3-4rj7-4ph4","summary":"Request smuggling leading to endpoint restriction bypass in Gunicorn","modified":"2026-09-10T03:50:00.309108086Z","packages":[{"ecosystem":"PyPI","name":"gunicorn","purl":"pkg:pypi/gunicorn","ranges":["<22.0.0"],"fixed":["22.0.0"]}]},{"id":"PYSEC-2026-1434","url":"https://osv.dev/vulnerability/PYSEC-2026-1434","summary":"Request smuggling leading to endpoint restriction bypass in Gunicorn","modified":"2026-07-07T17:47:39.221645615Z","packages":[{"ecosystem":"PyPI","name":"gunicorn","purl":"pkg:pypi/gunicorn","ranges":["<22.0.0"],"fixed":["22.0.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}