{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-113603",
        "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "state": "PUBLISHED",
        "assignerShortName": "VulnCheck",
        "dateReserved": "2026-10-20T11:48:49.343Z",
        "datePublished": "2026-10-20T15:40:30.742Z",
        "dateUpdated": "2026-10-21T15:54:28.895Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
                "shortName": "VulnCheck",
                "dateUpdated": "2026-10-20T15:40:30.742Z"
            },
            "datePublic": "2026-10-17T12:38:29.000Z",
            "title": "x402 @x402/extensions 2.3.1 through 2.28.0 SIWX Payment Bypass via PaymentPayload.resource",
            "descriptions": [
                {
                    "lang": "en",
                    "value": "The x402 SIWX server extension in @x402/extensions 2.3.1 through 2.28.0, x402 PyPI 2.11.0 through 2.25.0, and Go module 2.16.0 through 2.28.0 contains an authorization bypass vulnerability that allows paying clients to unlock unpaid routes by supplying a mismatched PaymentPayload.resource URL. Attackers can pay for the cheapest SIWX-protected route while setting resource.url to an expensive route, then repeatedly access it using only a SIGN-IN-WITH-X header without further payment."
                }
            ],
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "lang": "en",
                            "description": "Authorization Bypass Through User-Controlled Key",
                            "cweId": "CWE-639",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "affected": [
                {
                    "vendor": "x402-foundation",
                    "product": "@x402/extensions",
                    "defaultStatus": "unaffected",
                    "versions": [
                        {
                            "version": "2.3.1",
                            "lessThanOrEqual": "2.28.0",
                            "status": "affected",
                            "versionType": "semver"
                        }
                    ],
                    "packageURL": "pkg:npm/%40x402/extensions",
                    "repo": "https://github.com/x402-foundation/x402"
                },
                {
                    "vendor": "x402-foundation",
                    "product": "x402",
                    "defaultStatus": "unaffected",
                    "versions": [
                        {
                            "version": "2.11.0",
                            "lessThanOrEqual": "2.25.0",
                            "status": "affected",
                            "versionType": "semver"
                        }
                    ],
                    "repo": "https://github.com/x402-foundation/x402",
                    "packageURL": "pkg:pypi/x402"
                },
                {
                    "vendor": "x402-foundation",
                    "product": "github.com/x402-foundation/x402/go/v2",
                    "defaultStatus": "unaffected",
                    "versions": [
                        {
                            "version": "2.16.0",
                            "lessThanOrEqual": "2.28.0",
                            "status": "affected",
                            "versionType": "semver"
                        }
                    ],
                    "repo": "https://github.com/x402-foundation/x402",
                    "packageURL": "pkg:golang/github.com/x402-foundation/x402/go/v2"
                }
            ],
            "metrics": [
                {
                    "format": "CVSS",
                    "cvssV4_0": {
                        "version": "4.0",
                        "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N",
                        "attackVector": "NETWORK",
                        "attackComplexity": "LOW",
                        "attackRequirements": "NONE",
                        "privilegesRequired": "NONE",
                        "userInteraction": "NONE",
                        "vulnConfidentialityImpact": "LOW",
                        "vulnIntegrityImpact": "LOW",
                        "vulnAvailabilityImpact": "NONE",
                        "subConfidentialityImpact": "NONE",
                        "subIntegrityImpact": "NONE",
                        "subAvailabilityImpact": "NONE",
                        "baseScore": 6.9,
                        "baseSeverity": "MEDIUM"
                    }
                },
                {
                    "format": "CVSS",
                    "cvssV3_1": {
                        "version": "3.1",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
                        "attackVector": "NETWORK",
                        "attackComplexity": "LOW",
                        "privilegesRequired": "NONE",
                        "userInteraction": "NONE",
                        "scope": "UNCHANGED",
                        "confidentialityImpact": "LOW",
                        "integrityImpact": "LOW",
                        "availabilityImpact": "NONE",
                        "baseScore": 6.5,
                        "baseSeverity": "MEDIUM"
                    }
                }
            ],
            "references": [
                {
                    "url": "https://github.com/x402-foundation/x402/issues/3838",
                    "tags": [
                        "issue-tracking"
                    ]
                },
                {
                    "url": "https://github.com/x402-foundation/x402/pull/3840",
                    "tags": [
                        "patch",
                        "issue-tracking"
                    ]
                },
                {
                    "url": "https://github.com/x402-foundation/x402/blob/npm-@x402/extensions@v2.28.0/typescript/packages/extensions/src/sign-in-with-x/hooks.ts",
                    "tags": [
                        "technical-description"
                    ]
                },
                {
                    "url": "https://github.com/x402-foundation/x402/blob/pypi-x402@v2.25.0/python/x402/extensions/sign_in_with_x/hooks.py",
                    "tags": [
                        "technical-description"
                    ]
                },
                {
                    "url": "https://github.com/x402-foundation/x402/blob/go/v2.28.0/go/extensions/signinwithx/server.go",
                    "tags": [
                        "technical-description"
                    ]
                },
                {
                    "name": "VulnCheck Advisory: x402 @x402/extensions 2.3.1 through 2.28.0 SIWX Payment Bypass via PaymentPayload.resource",
                    "tags": [
                        "third-party-advisory"
                    ],
                    "url": "https://www.vulncheck.com/advisories/x402-x402-extensions-2.3.1-through-2.28.0-siwx-payment-bypass-via-paymentpayload-resource"
                }
            ],
            "credits": [
                {
                    "lang": "en",
                    "value": "CBF, Lza",
                    "type": "finder"
                }
            ],
            "x_generator": {
                "engine": "vulncheck-endgame"
            }
        },
        "adp": [
            {
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-10-21T14:40:26.284069Z",
                                "id": "CVE-2026-113603",
                                "options": [
                                    {
                                        "Exploitation": "none"
                                    },
                                    {
                                        "Automatable": "yes"
                                    },
                                    {
                                        "Technical Impact": "partial"
                                    }
                                ],
                                "role": "CISA Coordinator",
                                "version": "2.0.3"
                            }
                        }
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2026-10-21T15:54:28.895Z"
                }
            }
        ]
    }
}