{"id":"CVE-2026-40347","summary":"Python-Multipart affected by Denial of Service via large multipart preamble or epilogue data","details":"Python-Multipart is a streaming multipart parser for Python. Versions prior to 0.0.26 have a denial of service vulnerability when parsing crafted `multipart/form-data` requests with large preamble or epilogue sections. Upgrade to version 0.0.26 or later, which skips ahead to the next boundary candidate when processing leading CR/LF data and immediately discards epilogue data after the closing boundary.","aliases":["GHSA-mj87-hwqh-73pj"],"modified":"2026-06-18T03:54:26.511066413Z","published":"2026-04-17T23:56:50.777Z","related":["CGA-86pm-fp89-9wrv","SUSE-SU-2026:1544-1","SUSE-SU-2026:21999-1","openSUSE-SU-2026:10597-1","openSUSE-SU-2026:20846-1"],"database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-400","CWE-834"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40347.json"},"references":[{"type":"WEB","url":"https://github.com/Kludex/python-multipart/releases/tag/0.0.26"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40347.json"},{"type":"ADVISORY","url":"https://github.com/Kludex/python-multipart/security/advisories/GHSA-mj87-hwqh-73pj"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-40347"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/kludex/python-multipart","events":[{"introduced":"0"},{"fixed":"28f47859b4a40c2e11e02dc514b2e9743ceedd2e"}],"database_specific":{"cpe":"cpe:2.3:a:fastapiexpert:python-multipart:*:*:*:*:*:python:*:*","source":["AFFECTED_FIELD","CPE_RANGE","REFERENCES"],"extracted_events":[{"introduced":"0"},{"fixed":"0.0.26"},{"introduced":"0"},{"fixed":"0.0.26"}]}}],"versions":["0.0.25","0.0.24","0.0.23","0.0.22","0.0.21","0.0.20","0.0.19","0.0.18","0.0.17","0.0.16","0.0.15","0.0.14","0.0.13","0.0.12","0.0.11","0.0.10","0.0.9","0.0.8","0.0.7","0.0.6","0.0.5","0.0.4","0.0.2"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-40347.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"}]}