{"api_version":"1","generated_at":"2026-06-23T06:30:02+00:00","cve":"CVE-2026-55603","urls":{"html":"https://cve.report/CVE-2026-55603","api":"https://cve.report/api/cve/CVE-2026-55603.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-55603","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-55603"},"summary":{"title":"http-proxy-middleware: multipart/form-data field injection via unescaped CRLF in `fixRequestBody`","description":"http-proxy-middleware is node.js http-proxy middleware. From 3.0.4 until 3.0.7 and 4.1.1, fixRequestBody() is the library's documented helper for re-emitting a request body that was already consumed by a body parser. When the outgoing Content-Type is multipart/form-data, it rebuilds the body with handlerFormDataBodyData(), which interpolates each req.body key and value directly into the multipart wire format without neutralizing CR/LF. A \\r\\n inside a value (or key) lets an attacker close the current part and inject an entirely new form part. Because the proxy's own body parser saw a single opaque value, any gateway-side policy or validation performed on req.body is evaluated against a different set of fields than the upstream backend ultimately parses a request/parameter desynchronization across the trust boundary. This vulnerability is fixed in 3.0.7 and 4.1.1.","state":"PUBLISHED","assigner":"GitHub_M","published_at":"2026-06-22 21:16:26","updated_at":"2026-06-22 21:16:26"},"problem_types":["CWE-93","CWE-93 CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection')"],"metrics":[{"version":"3.1","source":"security-advisories@github.com","type":"Secondary","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"LOW","integrityImpact":"HIGH","availabilityImpact":"NONE"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N","data":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"LOW","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N","version":"3.1"}}],"references":[{"url":"https://github.com/chimurai/http-proxy-middleware/security/advisories/GHSA-gcq2-9pq2-cxqm","name":"https://github.com/chimurai/http-proxy-middleware/security/advisories/GHSA-gcq2-9pq2-cxqm","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-55603","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55603","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"chimurai","product":"http-proxy-middleware","version":"affected >= 3.0.4, < 3.0.7","platforms":[]},{"source":"CNA","vendor":"chimurai","product":"http-proxy-middleware","version":"affected >= 4.0.0, < 4.1.1","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"product":"http-proxy-middleware","vendor":"chimurai","versions":[{"status":"affected","version":">= 3.0.4, < 3.0.7"},{"status":"affected","version":">= 4.0.0, < 4.1.1"}]}],"descriptions":[{"lang":"en","value":"http-proxy-middleware is node.js http-proxy middleware. From 3.0.4 until 3.0.7 and 4.1.1, fixRequestBody() is the library's documented helper for re-emitting a request body that was already consumed by a body parser. When the outgoing Content-Type is multipart/form-data, it rebuilds the body with handlerFormDataBodyData(), which interpolates each req.body key and value directly into the multipart wire format without neutralizing CR/LF. A \\r\\n inside a value (or key) lets an attacker close the current part and inject an entirely new form part. Because the proxy's own body parser saw a single opaque value, any gateway-side policy or validation performed on req.body is evaluated against a different set of fields than the upstream backend ultimately parses a request/parameter desynchronization across the trust boundary. This vulnerability is fixed in 3.0.7 and 4.1.1."}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"LOW","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-93","description":"CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection')","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-06-22T20:07:05.034Z","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M"},"references":[{"name":"https://github.com/chimurai/http-proxy-middleware/security/advisories/GHSA-gcq2-9pq2-cxqm","tags":["x_refsource_CONFIRM"],"url":"https://github.com/chimurai/http-proxy-middleware/security/advisories/GHSA-gcq2-9pq2-cxqm"}],"source":{"advisory":"GHSA-gcq2-9pq2-cxqm","discovery":"UNKNOWN"},"title":"http-proxy-middleware: multipart/form-data field injection via unescaped CRLF in `fixRequestBody`"}},"cveMetadata":{"assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","assignerShortName":"GitHub_M","cveId":"CVE-2026-55603","datePublished":"2026-06-22T20:07:05.034Z","dateReserved":"2026-06-16T23:31:22.444Z","dateUpdated":"2026-06-22T20:07:05.034Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-06-22 21:16:26","lastModifiedDate":"2026-06-22 21:16:26","problem_types":["CWE-93","CWE-93 CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection')"],"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:C/C:L/I:H/A:N","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"LOW","integrityImpact":"HIGH","availabilityImpact":"NONE"},"exploitabilityScore":2.2,"impactScore":4.7}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"55603","Ordinal":"1","Title":"http-proxy-middleware: multipart/form-data field injection via u","CVE":"CVE-2026-55603","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"55603","Ordinal":"1","NoteData":"http-proxy-middleware is node.js http-proxy middleware. From 3.0.4 until 3.0.7 and 4.1.1, fixRequestBody() is the library's documented helper for re-emitting a request body that was already consumed by a body parser. When the outgoing Content-Type is multipart/form-data, it rebuilds the body with handlerFormDataBodyData(), which interpolates each req.body key and value directly into the multipart wire format without neutralizing CR/LF. A \\r\\n inside a value (or key) lets an attacker close the current part and inject an entirely new form part. Because the proxy's own body parser saw a single opaque value, any gateway-side policy or validation performed on req.body is evaluated against a different set of fields than the upstream backend ultimately parses a request/parameter desynchronization across the trust boundary. This vulnerability is fixed in 3.0.7 and 4.1.1.","Type":"Description","Title":"http-proxy-middleware: multipart/form-data field injection via u"}]}}}