{"api_version":"1","generated_at":"2026-06-24T15:06:20+00:00","cve":"CVE-2026-53537","urls":{"html":"https://cve.report/CVE-2026-53537","api":"https://cve.report/api/cve/CVE-2026-53537.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-53537","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-53537"},"summary":{"title":"Python-Multipart: Content-Disposition parameter smuggling via RFC 2231/5987 extended parameters","description":"Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.30, parse_options_header parsed Content-Disposition (and Content-Type) headers with email.message.Message, which transparently applies RFC 2231/5987 decoding. The extended parameter syntax (filename*=charset'lang'value, name*=..., and the filename*0/filename*1 continuation form) is decoded and surfaced under the bare filename/name key, and overrides the plain parameter when both are present. RFC 7578 §4.2 explicitly forbids the filename* form in multipart/form-data. Components that follow RFC 7578, or that do not implement RFC 2231/5987 decoding for multipart/form-data (WAFs, proxies, gateways), may interpret such a header differently. An attacker can exploit that difference to smuggle a different field name or filename past an upstream inspector to the backend. This vulnerability is fixed in 0.0.30.","state":"PUBLISHED","assigner":"GitHub_M","published_at":"2026-06-22 18:16:44","updated_at":"2026-06-23 17:17:03"},"problem_types":["CWE-20","CWE-436","CWE-20 CWE-20: Improper Input Validation","CWE-436 CWE-436: Interpretation Conflict"],"metrics":[{"version":"3.1","source":"security-advisories@github.com","type":"Secondary","score":"3.7","severity":"LOW","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","baseScore":3.7,"baseSeverity":"LOW","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"LOW","availabilityImpact":"NONE"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"3.7","severity":"LOW","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","data":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":3.7,"baseSeverity":"LOW","confidentialityImpact":"NONE","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","version":"3.1"}}],"references":[{"url":"https://github.com/Kludex/python-multipart/security/advisories/GHSA-vffw-93wf-4j4q","name":"https://github.com/Kludex/python-multipart/security/advisories/GHSA-vffw-93wf-4j4q","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-53537","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53537","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Kludex","product":"python-multipart","version":"affected < 0.0.30","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"53537","cve":"CVE-2026-53537","epss":"0.001760000","percentile":"0.071790000","score_date":"2026-06-23","updated_at":"2026-06-24 00:09:24"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"other":{"content":{"id":"CVE-2026-53537","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","timestamp":"2026-06-23T16:03:15.384645Z","version":"2.0.3"},"type":"ssvc"}}],"providerMetadata":{"dateUpdated":"2026-06-23T16:08:07.690Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"title":"CISA ADP Vulnrichment"}],"cna":{"affected":[{"product":"python-multipart","vendor":"Kludex","versions":[{"status":"affected","version":"< 0.0.30"}]}],"descriptions":[{"lang":"en","value":"Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.30, parse_options_header parsed Content-Disposition (and Content-Type) headers with email.message.Message, which transparently applies RFC 2231/5987 decoding. The extended parameter syntax (filename*=charset'lang'value, name*=..., and the filename*0/filename*1 continuation form) is decoded and surfaced under the bare filename/name key, and overrides the plain parameter when both are present. RFC 7578 §4.2 explicitly forbids the filename* form in multipart/form-data. Components that follow RFC 7578, or that do not implement RFC 2231/5987 decoding for multipart/form-data (WAFs, proxies, gateways), may interpret such a header differently. An attacker can exploit that difference to smuggle a different field name or filename past an upstream inspector to the backend. This vulnerability is fixed in 0.0.30."}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":3.7,"baseSeverity":"LOW","confidentialityImpact":"NONE","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-20","description":"CWE-20: Improper Input Validation","lang":"en","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-436","description":"CWE-436: Interpretation Conflict","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-06-22T16:57:21.496Z","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M"},"references":[{"name":"https://github.com/Kludex/python-multipart/security/advisories/GHSA-vffw-93wf-4j4q","tags":["x_refsource_CONFIRM"],"url":"https://github.com/Kludex/python-multipart/security/advisories/GHSA-vffw-93wf-4j4q"}],"source":{"advisory":"GHSA-vffw-93wf-4j4q","discovery":"UNKNOWN"},"title":"Python-Multipart: Content-Disposition parameter smuggling via RFC 2231/5987 extended parameters"}},"cveMetadata":{"assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","assignerShortName":"GitHub_M","cveId":"CVE-2026-53537","datePublished":"2026-06-22T16:57:21.496Z","dateReserved":"2026-06-09T18:13:07.262Z","dateUpdated":"2026-06-23T16:08:07.690Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-06-22 18:16:44","lastModifiedDate":"2026-06-23 17:17:03","problem_types":["CWE-20","CWE-436","CWE-20 CWE-20: Improper Input Validation","CWE-436 CWE-436: Interpretation Conflict"],"metrics":{"cvssMetricV31":[{"source":"security-advisories@github.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","baseScore":3.7,"baseSeverity":"LOW","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"LOW","availabilityImpact":"NONE"},"exploitabilityScore":2.2,"impactScore":1.4}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-06-23T16:03:15.384645Z","id":"CVE-2026-53537","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"53537","Ordinal":"1","Title":"Python-Multipart: Content-Disposition parameter smuggling via RF","CVE":"CVE-2026-53537","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"53537","Ordinal":"1","NoteData":"Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.30, parse_options_header parsed Content-Disposition (and Content-Type) headers with email.message.Message, which transparently applies RFC 2231/5987 decoding. The extended parameter syntax (filename*=charset'lang'value, name*=..., and the filename*0/filename*1 continuation form) is decoded and surfaced under the bare filename/name key, and overrides the plain parameter when both are present. RFC 7578 §4.2 explicitly forbids the filename* form in multipart/form-data. Components that follow RFC 7578, or that do not implement RFC 2231/5987 decoding for multipart/form-data (WAFs, proxies, gateways), may interpret such a header differently. An attacker can exploit that difference to smuggle a different field name or filename past an upstream inspector to the backend. This vulnerability is fixed in 0.0.30.","Type":"Description","Title":"Python-Multipart: Content-Disposition parameter smuggling via RF"}]}}}