{"id":"CVE-2026-42561","summary":"Python-Multipart: Denial of Service via unbounded multipart part headers","details":"Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.27, python-multipart has a denial of service vulnerability in multipart part header parsing. When parsing multipart/form-data, MultipartParser previously had no limit on the number of part headers or the size of an individual part header. An attacker could send a request with either many repeated headers without terminating the header block or a single very large header value, causing excessive CPU work before request rejection or completion. This vulnerability is fixed in 0.0.27.","aliases":["GHSA-pp6c-gr5w-3c5g"],"modified":"2026-06-18T03:55:37.980300953Z","published":"2026-05-13T20:55:11.767Z","related":["CGA-x6w5-pqjv-9j9c","SUSE-SU-2026:1961-1","SUSE-SU-2026:21999-1","openSUSE-SU-2026:10797-1","openSUSE-SU-2026:20846-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42561.json","cwe_ids":["CWE-770"],"cna_assigner":"GitHub_M"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42561.json"},{"type":"ADVISORY","url":"https://github.com/Kludex/python-multipart/security/advisories/GHSA-pp6c-gr5w-3c5g"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42561"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/kludex/python-multipart","events":[{"introduced":"0"},{"fixed":"6d1d6892a6b01b25da6f3e7b097e8e06c57fb250"}],"database_specific":{"source":"AFFECTED_FIELD","extracted_events":[{"introduced":"0"},{"fixed":"0.0.27"}]}}],"versions":["0.0.26","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-2026-42561.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:H"}]}