{"answers":{"affected":"4 open source packages ship an affected version, including http-proxy-middleware. It affects 1 product.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55603 exists.","fix":"Upgrade http-proxy-middleware to a fixed version for your release line: 3.0.7 or 4.1.1.","what":"CVE-2026-55603 is a high-severity vulnerability in chimurai http-proxy-middleware, published on 22 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-55603 and fix it if it is affected.\n\nWhat it is: CVE-2026-55603 is a high-severity vulnerability in chimurai http-proxy-middleware, published on 22 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55603 exists.\n\nAffected packages and fixed versions:\n- http-proxy-middleware (npm): affected from 3.0.4; fixed in 3.0.7\n- http-proxy-middleware (npm): affected from 3.0.4; fixed in 3.0.7\n- http-proxy-middleware (npm): affected from 4.0.0; fixed in 4.1.1\n- http-proxy-middleware (npm): affected from 4.0.0; fixed in 4.1.1\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-55603/ (Markdown: https://insights.sbomify.com/CVE-2026-55603/index.md)","id":"CVE-2026-55603","markdown":"https://insights.sbomify.com/CVE-2026-55603/index.md","name":"CVE-2026-55603","record":{"aliases":["ECHO-f223-e4bf-2265","GHSA-gcq2-9pq2-cxqm","MINI-4jjv-rwqw-g2j9","MINI-fh57-g8r4-chwc","MINI-fm5r-ph3h-g8qf","MINI-m846-mg27-9xxf","MINI-mp3p-7h88-j2r4","MINI-q8cr-26h2-9mvf","ROOT-APP-NPM-CVE-2026-55603"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["data_modify","security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"Node.js proxy middleware","requires_auth":"none","summary":"Attackers can inject CRLF sequences to desynchronize multipart form data between proxy and backend, bypassing validation and modifying request fields.","user_interaction":"not_required","vuln_class":"other"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"http-proxy-middleware","vendor":"chimurai"}],"cvss":{"score":7.5,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N","version":"3.1"},"cwes":[{"id":"CWE-93","name":"Improper Neutralization of CRLF Sequences"}],"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.","ecosystems":["npm"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":true,"headline":"http-proxy-middleware: multipart/form-data field injection via unescaped CRLF in `fixRequestBody`","id":"CVE-2026-55603","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"npm","product":null,"products":[],"type":"other","year":"2026"},"n_packages":4,"n_references":1,"next":{"headline":"@arikusi/deepseek-mcp-server has an Authorization Bypass Through User-Controlled Key","id":"CVE-2026-55604"},"packages":[{"ecosystem":"npm","fixed":["3.0.7"],"introduced":["3.0.4"],"last_affected":[],"package":"http-proxy-middleware","purl":null,"source":"GHSA-gcq2-9pq2-cxqm"},{"ecosystem":"npm","fixed":["3.0.7"],"introduced":["3.0.4"],"last_affected":[],"package":"http-proxy-middleware","purl":"pkg:npm/http-proxy-middleware","source":"GHSA-gcq2-9pq2-cxqm"},{"ecosystem":"npm","fixed":["4.1.1"],"introduced":["4.0.0"],"last_affected":[],"package":"http-proxy-middleware","purl":null,"source":"GHSA-gcq2-9pq2-cxqm"},{"ecosystem":"npm","fixed":["4.1.1"],"introduced":["4.0.0"],"last_affected":[],"package":"http-proxy-middleware","purl":"pkg:npm/http-proxy-middleware","source":"GHSA-gcq2-9pq2-cxqm"}],"prev":{"headline":"http-proxy-middleware `router` host+path substring matching allows Host-header-driven backend routing bypass","id":"CVE-2026-55602"},"products":["http-proxy-middleware"],"published":"2026-06-22","related":[{"cvss_score":8.7,"headline":"Denial of service in http-proxy-middleware","id":"CVE-2024-21536","kev_date_added":null,"published":"2024-10-19"},{"cvss_score":6.9,"headline":"http-proxy-middleware `router` host+path substring matching allows Host-header-driven backend routing bypass","id":"CVE-2026-55602","kev_date_added":null,"published":"2026-06-22"},{"cvss_score":4,"headline":"http-proxy-middleware can call writeBody twice because \"else if\" is not used","id":"CVE-2025-32996","kev_date_added":null,"published":"2025-04-15"},{"cvss_score":4,"headline":"http-proxy-middleware allows fixRequestBody to proceed even if bodyParser has failed","id":"CVE-2025-32997","kev_date_added":null,"published":"2025-04-15"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-06-23","vendors":["chimurai"]},"summary":"Attackers can inject CRLF sequences to desynchronize multipart form data between proxy and backend, bypassing validation and modifying request fields.","url":"https://insights.sbomify.com/CVE-2026-55603/"}