{"id":"CVE-2026-53540","summary":"Python-Multipart: Negative Content-Length in parse_form buffers the entire body in memory","details":"Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.31, parse_form() did not validate the Content-Length header before using it to bound its chunked read of the request body. A negative Content-Length turned the bounded read into a read-until-EOF, so the entire body was loaded into memory in a single read instead of in fixed-size chunks. This vulnerability is fixed in 0.0.31.","aliases":["GHSA-v9pg-7xvm-68hf"],"modified":"2026-07-08T08:13:46.587555057Z","published":"2026-06-22T16:58:54.923Z","related":["CGA-4chq-8f8m-cxg9","SUSE-SU-2026:22372-1","openSUSE-SU-2026:11099-1","openSUSE-SU-2026:21066-1"],"database_specific":{"cwe_ids":["CWE-1284"],"cna_assigner":"GitHub_M","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53540.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53540.json"},{"type":"ADVISORY","url":"https://github.com/Kludex/python-multipart/security/advisories/GHSA-v9pg-7xvm-68hf"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53540"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/kludex/python-multipart","events":[{"introduced":"0"},{"fixed":"4cffc68a165f7a6f6b7756ce006fabf07a05b7a4"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"0.0.31"}],"source":["AFFECTED_FIELD","CPE_RANGE"],"cpe":"cpe:2.3:a:fastapiexpert:python-multipart:*:*:*:*:*:python:*:*"}}],"versions":["0.0.30","0.0.29","0.0.28","0.0.27","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/cve-osv-conversion/osv-output/CVE-2026-53540.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L"}]}