CVE-2026-55603 (GCVE-0-2026-55603)

Vulnerability from cvelistv5 – Published: 2026-06-22 20:07 – Updated: 2026-06-23 12:21
VLAI
Title
http-proxy-middleware: multipart/form-data field injection via unescaped CRLF in `fixRequestBody`
Summary
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.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N
SSVC
Exploitation: poc Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-06-23 12:20 UTC
CWE
  • CWE-93 - Improper Neutralization of CRLF Sequences ('CRLF Injection')
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7994 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
chimurai http-proxy-middleware Affected: >= 3.0.4, < 3.0.7
Affected: >= 4.0.0, < 4.1.1
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-55603",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-23T12:20:45.426994Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-23T12:21:14.668Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/chimurai/http-proxy-middleware/security/advisories/GHSA-gcq2-9pq2-cxqm"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "http-proxy-middleware",
          "vendor": "chimurai",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 3.0.4, \u003c 3.0.7"
            },
            {
              "status": "affected",
              "version": "\u003e= 4.0.0, \u003c 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\u0027s 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\u0027s 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 (\u0027CRLF Injection\u0027)",
              "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": "2026-06-23T12:21:14.668Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-55603",
      "date": "2026-10-29",
      "epss": "0.00286",
      "percentile": "0.21074"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "product": "http-proxy-middleware",
                "vendor": "chimurai",
                "versions": [
                  {
                    "status": "affected",
                    "version": "\u003e= 3.0.4, \u003c 3.0.7"
                  },
                  {
                    "status": "affected",
                    "version": "\u003e= 4.0.0, \u003c 4.1.1"
                  }
                ]
              }
            ],
            "source": "security-advisories@github.com"
          }
        ],
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:a:chimurai:http-proxy-middleware:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "8281B19B-A543-4996-B6E0-3A43AD44585B",
                    "versionEndExcluding": "3.0.7",
                    "versionStartIncluding": "3.0.4",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:a:chimurai:http-proxy-middleware:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "D9D194C5-E95E-410C-BFB4-A36DCC12F656",
                    "versionEndExcluding": "4.1.1",
                    "versionStartIncluding": "4.0.0",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "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\u0027s 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\u0027s 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."
          },
          {
            "lang": "es",
            "value": "http-proxy-middleware es middleware de http-proxy de node.js. Desde 3.0.4 hasta 3.0.7 y 4.1.1, fixRequestBody() es el ayudante documentado de la biblioteca para reemitir un cuerpo de solicitud que ya fue consumido por un analizador de cuerpo. Cuando el Content-Type saliente es multipart/form-data, reconstruye el cuerpo con handlerFormDataBodyData(), que interpola cada clave y valor de req.body directamente en el formato de cable multipart sin neutralizar CR/LF. Un \\r\\n dentro de un valor (o clave) permite a un atacante cerrar la parte actual e inyectar una parte de formulario completamente nueva. Debido a que el propio analizador de cuerpo del proxy vio un \u00fanico valor opaco, cualquier pol\u00edtica o validaci\u00f3n del lado de la pasarela realizada en req.body se eval\u00faa contra un conjunto diferente de campos que los que el backend ascendente finalmente analiza, una desincronizaci\u00f3n de solicitud/par\u00e1metro a trav\u00e9s del l\u00edmite de confianza. Esta vulnerabilidad est\u00e1 corregida en 3.0.7 y 4.1.1."
          }
        ],
        "id": "CVE-2026-55603",
        "lastModified": "2026-10-25T23:10:00.167",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "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"
              },
              "exploitabilityScore": 2.2,
              "impactScore": 4.7,
              "source": "security-advisories@github.com",
              "type": "Secondary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2026-55603",
                "options": [
                  {
                    "exploitation": "poc"
                  },
                  {
                    "automatable": "no"
                  },
                  {
                    "technicalImpact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-23T12:20:45.426994Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2026-06-22T21:16:26.033",
        "references": [
          {
            "source": "security-advisories@github.com",
            "tags": [
              "Exploit",
              "Mitigation",
              "Vendor Advisory"
            ],
            "url": "https://github.com/chimurai/http-proxy-middleware/security/advisories/GHSA-gcq2-9pq2-cxqm"
          },
          {
            "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
            "tags": [
              "Exploit",
              "Mitigation",
              "Vendor Advisory"
            ],
            "url": "https://github.com/chimurai/http-proxy-middleware/security/advisories/GHSA-gcq2-9pq2-cxqm"
          }
        ],
        "sourceIdentifier": "security-advisories@github.com",
        "vulnStatus": "Analyzed",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-93"
              }
            ],
            "source": "security-advisories@github.com",
            "type": "Secondary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-10-27T05:04:07+00:00",
      "cve": "CVE-2026-55603",
      "id": "CVE-2026-55603",
      "initial_release_date": "2026-06-22T20:07:05.034000+00:00",
      "product_status:fixed": "3",
      "product_status:known_affected": "1",
      "product_status:known_not_affected": "94",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "http-proxy-middleware: http-proxy-middleware: Data integrity compromise via CR/LF injection",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-55603.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-55603",
                    "options": [
                      {
                        "Exploitation": "poc"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-06-23T12:20:45.426994Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-06-23T12:21:10.631Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "references": [
              {
                "tags": [
                  "exploit"
                ],
                "url": "https://github.com/chimurai/http-proxy-middleware/security/advisories/GHSA-gcq2-9pq2-cxqm"
              }
            ],
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "product": "http-proxy-middleware",
              "vendor": "chimurai",
              "versions": [
                {
                  "status": "affected",
                  "version": "\u003e= 3.0.4, \u003c 3.0.7"
                },
                {
                  "status": "affected",
                  "version": "\u003e= 4.0.0, \u003c 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\u0027s 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\u0027s 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 (\u0027CRLF Injection\u0027)",
                  "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": "2026-06-23T12:21:14.668Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON

Loading timeline…




    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.