CVE Catalog

CVE-2026-113603

MediumCVSS 6.5
Published: Updated: Translated: NVD NIST

Summary

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.

Risk Assessment

An attacker can gain unauthorized access to paid routes without paying, causing financial losses. This can undermine the billing model and service integrity.

Recommendation

Update @x402/extensions, x402 PyPI, and the Go module to versions later than the listed ranges. Verify the resource URL validation logic in payments.

Related vulnerabilities

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS