CVE-2026-111763 (GCVE-0-2026-111763)

Vulnerability from cvelistv5 – Published: 2026-10-20 15:03 – Updated: 2026-10-20 15:03
VLAI
Title
A2A Java SDK send client credentials under server-controlled HTTP header name, enabling leakage via redirect
Summary
A2A Java SDK is the official Java SDK for the Agent2Agent (A2A) Protocol. Prior to 1.3.0.Final, a malicious or compromised remote agent can cause the default JDK-based client to forward a configured API key to a third-party server. When a client application configures credentials through `CredentialService`, `AuthInterceptor.intercept` in `client/transport/spi/src/main/java/org/a2aproject/sdk/client/transport/spi/interceptors/auth/AuthInterceptor.java` uses `APIKeySecurityScheme.name()` from the remote AgentCard directly as the HTTP header name containing the credential, without checking that the declared location is HEADER. JdkA2AHttpClient uses followRedirects(NORMAL), so an agent-controlled cross-origin redirect forwards the custom credential-bearing header even when the standard Authorization header is stripped. The attack requires configured API key credentials for the agent's security scheme and control of the agent's AgentCard and redirect response, but no additional client privileges. This issue is fixed in version 1.3.0.Final.
Severity
5.7 (Medium)
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
CWE
  • CWE-522 - Insufficiently Protected Credentials
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7639 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
a2aproject a2a-java Affected: < 1.3.0.Final
guessed Create a notification for this product.
Show details on NVD website
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{
  "containers": {
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          "product": "a2a-java",
          "vendor": "a2aproject",
          "versions": [
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              "version": "\u003c 1.3.0.Final"
            }
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          "lang": "en",
          "value": "A2A Java SDK is the official Java SDK for the Agent2Agent (A2A) Protocol. Prior to 1.3.0.Final, a malicious or compromised remote agent can cause the default JDK-based client to forward a configured API key to a third-party server. When a client application configures credentials through `CredentialService`, `AuthInterceptor.intercept` in `client/transport/spi/src/main/java/org/a2aproject/sdk/client/transport/spi/interceptors/auth/AuthInterceptor.java` uses `APIKeySecurityScheme.name()` from the remote AgentCard directly as the HTTP header name containing the credential, without checking that the declared location is HEADER. JdkA2AHttpClient uses followRedirects(NORMAL), so an agent-controlled cross-origin redirect forwards the custom credential-bearing header even when the standard Authorization header is stripped. The attack requires configured API key credentials for the agent\u0027s security scheme and control of the agent\u0027s AgentCard and redirect response, but no additional client privileges. This issue is fixed in version 1.3.0.Final."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "LOCAL",
            "baseScore": 5.7,
            "baseSeverity": "MEDIUM",
            "privilegesRequired": "LOW",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "NONE"
          }
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              "description": "CWE-522: Insufficiently Protected Credentials",
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            }
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      "providerMetadata": {
        "dateUpdated": "2026-10-20T15:03:28.034Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
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          "name": "https://github.com/a2aproject/a2a-java/security/advisories/GHSA-9rhm-2h4x-jwmx",
          "tags": [
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          "url": "https://github.com/a2aproject/a2a-java/security/advisories/GHSA-9rhm-2h4x-jwmx"
        },
        {
          "name": "https://github.com/a2aproject/a2a-java/security/advisories/GHSA-4fpj-g9jf-9rgg",
          "tags": [
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          ],
          "url": "https://github.com/a2aproject/a2a-java/security/advisories/GHSA-4fpj-g9jf-9rgg"
        },
        {
          "name": "https://github.com/a2aproject/a2a-java/pull/1097",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/a2aproject/a2a-java/pull/1097"
        },
        {
          "name": "https://github.com/a2aproject/a2a-java/commit/2a36530d75e11bcf9b81f543464dbe193ca6478e",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/a2aproject/a2a-java/commit/2a36530d75e11bcf9b81f543464dbe193ca6478e"
        },
        {
          "name": "https://github.com/a2aproject/a2a-java/releases/tag/v1.3.0.Final",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/a2aproject/a2a-java/releases/tag/v1.3.0.Final"
        }
      ],
      "source": {
        "advisory": "GHSA-9rhm-2h4x-jwmx",
        "discovery": "UNKNOWN"
      },
      "title": "A2A Java SDK send client credentials under server-controlled HTTP header name, enabling leakage via redirect"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-111763",
    "datePublished": "2026-10-20T15:03:28.034Z",
    "dateReserved": "2026-10-16T17:52:09.082Z",
    "dateUpdated": "2026-10-20T15:03:28.034Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": {
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        "affected": [
          {
            "affectedData": [
              {
                "product": "a2a-java",
                "vendor": "a2aproject",
                "versions": [
                  {
                    "status": "affected",
                    "version": "\u003c 1.3.0.Final"
                  }
                ]
              }
            ],
            "source": "security-advisories@github.com"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "A2A Java SDK is the official Java SDK for the Agent2Agent (A2A) Protocol. Prior to 1.3.0.Final, a malicious or compromised remote agent can cause the default JDK-based client to forward a configured API key to a third-party server. When a client application configures credentials through `CredentialService`, `AuthInterceptor.intercept` in `client/transport/spi/src/main/java/org/a2aproject/sdk/client/transport/spi/interceptors/auth/AuthInterceptor.java` uses `APIKeySecurityScheme.name()` from the remote AgentCard directly as the HTTP header name containing the credential, without checking that the declared location is HEADER. JdkA2AHttpClient uses followRedirects(NORMAL), so an agent-controlled cross-origin redirect forwards the custom credential-bearing header even when the standard Authorization header is stripped. The attack requires configured API key credentials for the agent\u0027s security scheme and control of the agent\u0027s AgentCard and redirect response, but no additional client privileges. This issue is fixed in version 1.3.0.Final."
          }
        ],
        "id": "CVE-2026-111763",
        "lastModified": "2026-10-20T19:48:50.250",
        "metrics": {
          "cvssMetricV40": [
            {
              "cvssData": {
                "Automatable": "NOT_DEFINED",
                "Recovery": "NOT_DEFINED",
                "Safety": "NOT_DEFINED",
                "attackComplexity": "LOW",
                "attackRequirements": "PRESENT",
                "attackVector": "LOCAL",
                "availabilityRequirement": "NOT_DEFINED",
                "baseScore": 5.7,
                "baseSeverity": "MEDIUM",
                "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": "LOW",
                "providerUrgency": "NOT_DEFINED",
                "subAvailabilityImpact": "NONE",
                "subConfidentialityImpact": "NONE",
                "subIntegrityImpact": "NONE",
                "userInteraction": "NONE",
                "valueDensity": "NOT_DEFINED",
                "vectorString": "CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/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": "NONE",
                "vulnConfidentialityImpact": "HIGH",
                "vulnIntegrityImpact": "NONE",
                "vulnerabilityResponseEffort": "NOT_DEFINED"
              },
              "source": "security-advisories@github.com",
              "type": "Secondary"
            }
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        },
        "published": "2026-10-20T16:17:00.550",
        "references": [
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            "source": "security-advisories@github.com",
            "url": "https://github.com/a2aproject/a2a-java/commit/2a36530d75e11bcf9b81f543464dbe193ca6478e"
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          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/a2aproject/a2a-java/pull/1097"
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          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/a2aproject/a2a-java/releases/tag/v1.3.0.Final"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/a2aproject/a2a-java/security/advisories/GHSA-4fpj-g9jf-9rgg"
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          {
            "source": "security-advisories@github.com",
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          }
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        "sourceIdentifier": "security-advisories@github.com",
        "vulnStatus": "Awaiting Analysis",
        "weaknesses": [
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            "description": [
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                "lang": "en",
                "value": "CWE-522"
              }
            ],
            "source": "security-advisories@github.com",
            "type": "Primary"
          }
        ]
      }
    }
  }
}



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