CVEvulnerability
CVE-2026-113603
6.9 MEDIUM
Official page ↗
- Status
- Awaiting Analysis
- Published
- 2026-10-20
- Last modified
- 2026-10-21
- Assigner
- [email protected]
- CVSS 4.0 ([email protected])
- 6.9 MEDIUM — 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/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
- CVSS 3.1 ([email protected])
- 6.5 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
- Weaknesses
- CWE-639
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.
Related
Weakness · CWE (1)
- CWE-639 Authorization Bypass Through User-Controlled Key weakness
References
- https://github.com/x402-foundation/x402/blob/go/v2.28.0/go/extensions/signinwithx/server.go github.com
- https://github.com/x402-foundation/x402/blob/npm-@x402/[email protected]/typescript/packages/extensions/src/sign-in-with-x/hooks.ts github.com
- https://github.com/x402-foundation/x402/blob/[email protected]/python/x402/extensions/sign_in_with_x/hooks.py github.com
- https://github.com/x402-foundation/x402/issues/3838 github.com
- https://github.com/x402-foundation/x402/pull/3840 github.com
- https://www.vulncheck.com/advisories/x402-x402-extensions-2.3.1-through-2.28.0-siwx-payment-bypass-via-paymentpayload-resource www.vulncheck.com