CVE-2026-113603
CVE-2026-113603 · x402 @x402/extensions 2.3.1 through 2.28.0 SIWX Payment Bypass via PaymentPayload.resource
This page contains facts from public vulnerability sources. Check the original advisory before updating.
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.
CVSS 6.9 · Medium · EPSS 0.3%
- Published
- Updated
Affected products and versions
@x402/extensions
- Versions
- ≥ 2.3.1, ≤ 2.28.0: Affected (semver)
No fix published
x402
- Versions
- ≥ 2.11.0, ≤ 2.25.0: Affected (semver)
No fix published
github.com/x402-foundation/x402/go/v2
- Versions
- ≥ 2.16.0, ≤ 2.28.0: Affected (semver)
No fix published
Original sources
- 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/[email protected]/typescript/packages/extensions/src/sign-in-with-x/hooks.ts
- https://github.com/x402-foundation/x402/blob/[email protected]/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
- https://nvd.nist.gov/vuln/detail/CVE-2026-113603