{"id":"CVE-2026-113603","revision":null,"records":[{"revision":"4a2305b4e80442db9d36fd5eba5551ae","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-113603","aliases":[],"title":"x402 @x402/extensions 2.3.1 through 2.28.0 SIWX Payment Bypass via PaymentPayload.resource","description":"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.","state":0,"publishedAt":"2026-10-20T15:40:30.742+00:00","modifiedAt":"2026-10-21T15:54:28.895+00:00","affected":[{"ecosystem":"Vendor product","name":"@x402/extensions","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"x402-foundation\",\n                    \"product\": \"@x402/extensions\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"versions\": [\n                        {\n                            \"version\": \"2.3.1\",\n                            \"lessThanOrEqual\": \"2.28.0\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        }\n                    ],\n                    \"packageURL\": \"pkg:npm/%40x402/extensions\",\n                    \"repo\": \"https://github.com/x402-foundation/x402\"\n                }"},{"ecosystem":"Vendor product","name":"x402","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"x402-foundation\",\n                    \"product\": \"x402\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"versions\": [\n                        {\n                            \"version\": \"2.11.0\",\n                            \"lessThanOrEqual\": \"2.25.0\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        }\n                    ],\n                    \"repo\": \"https://github.com/x402-foundation/x402\",\n                    \"packageURL\": \"pkg:pypi/x402\"\n                }"},{"ecosystem":"Vendor product","name":"github.com/x402-foundation/x402/go/v2","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"x402-foundation\",\n                    \"product\": \"github.com/x402-foundation/x402/go/v2\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"versions\": [\n                        {\n                            \"version\": \"2.16.0\",\n                            \"lessThanOrEqual\": \"2.28.0\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        }\n                    ],\n                    \"repo\": \"https://github.com/x402-foundation/x402\",\n                    \"packageURL\": \"pkg:golang/github.com/x402-foundation/x402/go/v2\"\n                }"}],"metrics":[{"system":"CVSS 4.0","vector":"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","score":6.9,"severity":"MEDIUM"},{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","score":6.5,"severity":"MEDIUM"}],"references":["https://github.com/x402-foundation/x402/issues/3838","https://github.com/x402-foundation/x402/pull/3840","https://github.com/x402-foundation/x402/blob/npm-@x402/extensions@v2.28.0/typescript/packages/extensions/src/sign-in-with-x/hooks.ts","https://github.com/x402-foundation/x402/blob/pypi-x402@v2.25.0/python/x402/extensions/sign_in_with_x/hooks.py","https://github.com/x402-foundation/x402/blob/go/v2.28.0/go/extensions/signinwithx/server.go","https://www.vulncheck.com/advisories/x402-x402-extensions-2.3.1-through-2.28.0-siwx-payment-bypass-via-paymentpayload-resource"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-113603","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-113603","identifiers":["CVE-2026-113603"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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