CVE-2026-63344 (GCVE-0-2026-63344)

Vulnerability from cvelistv5 – Published: 2026-10-30 22:15 – Updated: 2026-10-30 22:15
VLAI
Title
Refitter: C# source injection through OpenAPI content-type map keys
Summary
Refitter is a tool for generating a C# REST API client using the Refit library. Prior to 2.1.2, content-type keys in the content maps of `requestBody/responses` are emitted verbatim into a Refit `[Headers("Accept: <ct>", "Content-Type: <ct>")]` attribute string without escaping quotation marks. A crafted content-type key in an attacker-influenced OpenAPI description survives default validation without `--skip-validation`, breaks out of the attribute string and enclosing interface and namespace, and can introduce a top-level file class while leaving valid generated C#. A `[ModuleInitializer]` method in that class executes attacker code when the generated assembly is loaded at application startup, without requiring a call to the client. The behavior was verified with Refitter 2.0.0 and .NET 8. This issue is fixed in version 2.1.2.
Severity
8.6 (High)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CWE
  • CWE-94 - Improper Control of Generation of Code ('Code Injection')
  • CWE-116 - Improper Encoding or Escaping of Output
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 8016 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
christianhelle refitter Affected: < 2.1.2
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "refitter",
          "vendor": "christianhelle",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2.1.2"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Refitter is a tool for generating a C# REST API client using the Refit library. Prior to 2.1.2, content-type keys in the content maps of `requestBody/responses` are emitted verbatim into a Refit `[Headers(\"Accept: \u003cct\u003e\", \"Content-Type: \u003cct\u003e\")]` attribute string without escaping quotation marks. A crafted content-type key in an attacker-influenced OpenAPI description survives default validation without `--skip-validation`, breaks out of the attribute string and enclosing interface and namespace, and can introduce a top-level file class while leaving valid generated C#. A `[ModuleInitializer]` method in that class executes attacker code when the generated assembly is loaded at application startup, without requiring a call to the client. The behavior was verified with Refitter 2.0.0 and .NET 8. This issue is fixed in version 2.1.2."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 8.6,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "ACTIVE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-94",
              "description": "CWE-94: Improper Control of Generation of Code (\u0027Code Injection\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-116",
              "description": "CWE-116: Improper Encoding or Escaping of Output",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-30T22:15:27.846Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/christianhelle/refitter/security/advisories/GHSA-p32v-8v8j-j534",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/christianhelle/refitter/security/advisories/GHSA-p32v-8v8j-j534"
        },
        {
          "name": "https://github.com/christianhelle/refitter/pull/1178",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/christianhelle/refitter/pull/1178"
        },
        {
          "name": "https://github.com/christianhelle/refitter/commit/ab4d8e439d6f0ee82ad49ee15323978d70fe5a67",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/christianhelle/refitter/commit/ab4d8e439d6f0ee82ad49ee15323978d70fe5a67"
        },
        {
          "name": "https://github.com/christianhelle/refitter/releases/tag/2.1.2",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/christianhelle/refitter/releases/tag/2.1.2"
        },
        {
          "name": "https://github.com/user-attachments/files/29394848/reproduce.sh",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/user-attachments/files/29394848/reproduce.sh"
        },
        {
          "name": "https://github.com/user-attachments/files/29394851/maintainer-report.txt",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/user-attachments/files/29394851/maintainer-report.txt"
        },
        {
          "name": "https://github.com/user-attachments/files/29394853/make_spec.py",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/user-attachments/files/29394853/make_spec.py"
        }
      ],
      "source": {
        "advisory": "GHSA-p32v-8v8j-j534",
        "discovery": "UNKNOWN"
      },
      "title": "Refitter: C# source injection through OpenAPI content-type map keys"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-63344",
    "datePublished": "2026-10-30T22:15:27.846Z",
    "dateReserved": "2026-07-16T14:14:24.385Z",
    "dateUpdated": "2026-10-30T22:15:27.846Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-63344",
      "date": "2026-11-02",
      "epss": "0.0035",
      "percentile": "0.28695"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "product": "refitter",
                "vendor": "christianhelle",
                "versions": [
                  {
                    "status": "affected",
                    "version": "\u003c 2.1.2"
                  }
                ]
              }
            ],
            "source": "security-advisories@github.com"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "Refitter is a tool for generating a C# REST API client using the Refit library. Prior to 2.1.2, content-type keys in the content maps of `requestBody/responses` are emitted verbatim into a Refit `[Headers(\"Accept: \u003cct\u003e\", \"Content-Type: \u003cct\u003e\")]` attribute string without escaping quotation marks. A crafted content-type key in an attacker-influenced OpenAPI description survives default validation without `--skip-validation`, breaks out of the attribute string and enclosing interface and namespace, and can introduce a top-level file class while leaving valid generated C#. A `[ModuleInitializer]` method in that class executes attacker code when the generated assembly is loaded at application startup, without requiring a call to the client. The behavior was verified with Refitter 2.0.0 and .NET 8. This issue is fixed in version 2.1.2."
          }
        ],
        "id": "CVE-2026-63344",
        "lastModified": "2026-11-02T19:35:33.347",
        "metrics": {
          "cvssMetricV40": [
            {
              "cvssData": {
                "Automatable": "NOT_DEFINED",
                "Recovery": "NOT_DEFINED",
                "Safety": "NOT_DEFINED",
                "attackComplexity": "LOW",
                "attackRequirements": "NONE",
                "attackVector": "NETWORK",
                "availabilityRequirement": "NOT_DEFINED",
                "baseScore": 8.6,
                "baseSeverity": "HIGH",
                "confidentialityRequirement": "NOT_DEFINED",
                "exploitMaturity": "NOT_DEFINED",
                "integrityRequirement": "NOT_DEFINED",
                "modifiedAttackComplexity": "NOT_DEFINED",
                "modifiedAttackRequirements": "NOT_DEFINED",
                "modifiedAttackVector": "NOT_DEFINED",
                "modifiedPrivilegesRequired": "NOT_DEFINED",
                "modifiedSubAvailabilityImpact": "NOT_DEFINED",
                "modifiedSubConfidentialityImpact": "NOT_DEFINED",
                "modifiedSubIntegrityImpact": "NOT_DEFINED",
                "modifiedUserInteraction": "NOT_DEFINED",
                "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
                "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
                "modifiedVulnIntegrityImpact": "NOT_DEFINED",
                "privilegesRequired": "NONE",
                "providerUrgency": "NOT_DEFINED",
                "subAvailabilityImpact": "NONE",
                "subConfidentialityImpact": "NONE",
                "subIntegrityImpact": "NONE",
                "userInteraction": "ACTIVE",
                "valueDensity": "NOT_DEFINED",
                "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
                "version": "4.0",
                "vulnAvailabilityImpact": "HIGH",
                "vulnConfidentialityImpact": "HIGH",
                "vulnIntegrityImpact": "HIGH",
                "vulnerabilityResponseEffort": "NOT_DEFINED"
              },
              "source": "security-advisories@github.com",
              "type": "Secondary"
            }
          ]
        },
        "published": "2026-10-30T23:17:13.840",
        "references": [
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/christianhelle/refitter/commit/ab4d8e439d6f0ee82ad49ee15323978d70fe5a67"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/christianhelle/refitter/pull/1178"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/christianhelle/refitter/releases/tag/2.1.2"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/christianhelle/refitter/security/advisories/GHSA-p32v-8v8j-j534"
          },
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            "source": "security-advisories@github.com",
            "url": "https://github.com/user-attachments/files/29394848/reproduce.sh"
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            "source": "security-advisories@github.com",
            "url": "https://github.com/user-attachments/files/29394851/maintainer-report.txt"
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            "source": "security-advisories@github.com",
            "url": "https://github.com/user-attachments/files/29394853/make_spec.py"
          }
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        "sourceIdentifier": "security-advisories@github.com",
        "vulnStatus": "Deferred",
        "weaknesses": [
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            "description": [
              {
                "lang": "en",
                "value": "CWE-94"
              },
              {
                "lang": "en",
                "value": "CWE-116"
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            ],
            "source": "security-advisories@github.com",
            "type": "Primary"
          }
        ]
      }
    }
  }
}



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