CVE Catalog

CVE-2026-48819

MediumCVSS 4.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.22%

13th percentile - higher than 13% of all known CVEs

Summary

Hey API before version 0.97.3 has a vulnerability in generated SDKs where slot-prefixed keys (e.g., $query__proto__) are written directly to the corresponding slot, allowing an attacker to set the object prototype and inject controlled keys during for..in iteration.

Risk Assessment

An attacker can manipulate object prototypes in the generated SDK, potentially leading to unexpected application behavior, data leakage, or further attacks.

Recommendation

Upgrade Hey API to version 0.97.3 or later. Review generated SDKs for unusual keys and apply appropriate sanitization.

Related vulnerabilities

Original NVD description (English source)

Hey API is an ecosystem for turning API specifications into production-ready code. Prior to 0.97.3, dist/clients/core/params.ts ships a runtime template copied into generated SDKs as params.gen.ts, and buildClientParams writes unknown slot-prefixed keys such as $body_, $headers_, $path_, and $query_ directly to the corresponding slot, allowing $query___proto__ alongside a legitimate q field to set params.query through params["query"]["__proto__"] = value, call Object.setPrototypeOf(params.query, value), and expose inherited attacker-controlled keys during for..in iteration. This issue is fixed in version 0.97.3.

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