What is CVE-2026-28794?

CVE-2026-28794 is a critical-severity vulnerability in Middleapi Orpc, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 9.8/10. Published 2026-03-06.

How severe is CVE-2026-28794?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Prototype Pollution in Middleapi Orpc

CVE-2026-28794

oRPC is an tool that helps build APIs that are end-to-end type-safe and adhere to OpenAPI standards. Prior to version 1.13.6, a prototype pollution vulnerability exists in the RPC JSON deserializer of the @orpc/client package. The vulnerability allows unauthenticated, remote attackers to inject arbitrary properties into the global Object.prototype. Because this pollution persists for the lifetime of the Node.js process and affects all objects, it can lead to severe security breaches, including authentication bypass, denial of service, and potentially Remote Code Execution. This issue has been patched in version 1.13.6.

Vulnerability class: Prototype Pollution

EPSS: 0.009 (56.4th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Middleapi Orpc — versions < 1.13.6
Orpc

Weakness classification (CWE)

CWE-1321 — Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution)

References

security-advisories@github.com (x_refsource_CONFIRM, Exploit, Vendor Advisory)
security-advisories@github.com (Patch, x_refsource_MISC)

Frequently asked questions

What is CVE-2026-28794?: CVE-2026-28794 is a critical-severity vulnerability in Middleapi Orpc, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 9.8/10. Published 2026-03-06.
How severe is CVE-2026-28794?: Critical severity. CVSS v3 base score is 9.8 out of 10.