CVE-2026-48819

4.8 MEDIUM 0.3% exploit odds Fix listed Other

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in. Limited direct impact.
Exploit odds: 0.3% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-07-17 20:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-24 20:10 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.3% in the next 30 days (EPSS).
Severity: 4.8 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-07-17 20:17 UTC
Last modified: 2026-10-24 20:10 UTC
Exploit probability: 0.3% · EPSS, next 30 days
Weakness: CWE-1321 · Prototype pollution
Record status: Deferred

Attack profile CVSS 3.1 · 4.8

Attack vector: Network
Complexity: High
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: None

Raw vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-48819.md and follow it. Check whether this project is affected by CVE-2026-48819. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record