{"schema":"threatline.record/2","record":{"id":"CVE-2026-113603","aliases":[],"summary":"x402 @x402/extensions 2.3.1 through 2.28.0 SIWX Payment Bypass via PaymentPayload.resource","details":"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.","categories":["Unclassified"],"product":"@x402/extensions","vendor":"x402-foundation","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-113603","source_modified_at":"2026-10-21T15:54:28.895Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"@x402/extensions","vendor":"x402-foundation","versions":[{"version":"2.3.1","lessThanOrEqual":"2.28.0","status":"affected","versionType":"semver"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-113603","source_modified_at":"2026-10-21T15:54:28.895Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"x402","vendor":"x402-foundation","versions":[{"version":"2.11.0","lessThanOrEqual":"2.25.0","status":"affected","versionType":"semver"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-113603","source_modified_at":"2026-10-21T15:54:28.895Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"github.com/x402-foundation/x402/go/v2","vendor":"x402-foundation","versions":[{"version":"2.16.0","lessThanOrEqual":"2.28.0","status":"affected","versionType":"semver"}],"defaultStatus":"unaffected"}],"fixed_versions":[],"cvss":6.9,"severity":"Medium","kev":{"listed":false},"epss":{"probability":0.00291,"percentile":0.20569,"score_date":"2026-10-23"},"published_at":"2026-10-20T15:40:30.742Z","modified_at":"2026-10-21T15:54:28.895Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-113603","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-21T15:54:28.895Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-113603","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://github.com/x402-foundation/x402/issues/3838","tags":["issue-tracking"]},{"source":"CVE List","url":"https://github.com/x402-foundation/x402/pull/3840","tags":["patch","issue-tracking"]},{"source":"CVE List","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"]},{"source":"CVE List","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"]},{"source":"CVE List","url":"https://github.com/x402-foundation/x402/blob/go/v2.28.0/go/extensions/signinwithx/server.go","tags":["technical-description"]},{"source":"CVE List","url":"https://www.vulncheck.com/advisories/x402-x402-extensions-2.3.1-through-2.28.0-siwx-payment-bypass-via-paymentpayload-resource","tags":["third-party-advisory"]}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CVE List","ssvc":{"exploitation":"none","automatable":"yes","technical_impact":"partial","assessed_at":"2026-10-21T14:40:26.284069Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":null,"confidence":"unknown","reviewed":false},"change_timestamp":"2026-10-21T15:54:28.895Z","content_hash":"e0b55e49a34139ef7a75ee1f71d2a6b1edd1050d48c0d3568753f911a07a9059"}}