{"id":"CVE-2026-55603","revision":"d67a12f6648b4386967cea44a22a3522","records":[{"revision":"d67a12f6648b4386967cea44a22a3522","observedAt":"2026-10-25T14:19:05.298+00:00","statement":{"source":"nvd","id":"CVE-2026-55603","aliases":[],"title":"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 Conte…","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":0,"publishedAt":"2026-06-22T21:16:26.033+00:00","modifiedAt":"2026-06-24T16:44:28.87+00:00","affected":[],"metrics":[{"system":"CVSS 3.1 · security-advisories@github.com · Secondary","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N","score":7.5,"severity":"HIGH"}],"references":["https://github.com/chimurai/http-proxy-middleware/security/advisories/GHSA-gcq2-9pq2-cxqm"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-55603","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Analyzed","weaknesses":["CWE-93"],"productCriteria":["cpe:2.3:a:chimurai:http-proxy-middleware:*:*:*:*:*:*:*:*"],"sourceDates":{"published":"2026-06-22T21:16:26.033","lastModified":"2026-06-24T16:44:28.870"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-55603","identifiers":["CVE-2026-55603"]},"retained":false,"historicalAffected":[]}],"coverage":[]}