# CVE-2026-103918: @orpc/zod: Prototype injection in smart coercion

> Remote attackers can inject prototype properties via crafted inputs in oRPC Zod plugins, potentially leading to code execution or denial of service.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 2 Oct 2026
- **Updated:** 5 Oct 2026
- **Also known as:** GHSA-gcgf-fh7c-8gf2

## What is CVE-2026-103918?

CVE-2026-103918 is a medium-severity unsafe deserialization vulnerability in middleapi orpc, published on 2 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

oRPC is a tool that helps build APIs that are end-to-end type-safe and adhere to OpenAPI standards. Prior to 1.14.10, the @orpc/zod ZodSmartCoercionPlugin and experimental_ZodSmartCoercionPlugin collect object and record properties in plain objects and resolve shape keys through the prototype chain. A remote client that can reach a procedure with an object or record input can supply __proto__ to replace the prototype of the returned request object, allowing attacker-controlled inherited values to reach application lookups. For object schemas, keys such as constructor, toString, and __proto__ can instead resolve inherited members as Zod schemas and cause an unhandled TypeError before validation. The global Object.prototype, unrelated objects, other requests, and other users are not modified, and the availability effect is limited to crafted requests rather than persistent process-wide state. This issue is fixed in version 1.14.10.

Weakness: CWE-915 (Improperly Controlled Modification of Dynamically-Determined Object Attributes), CWE-1321 (Improperly Controlled Modification of Object Prototype Attributes)

## Which versions are affected by CVE-2026-103918?

2 open source packages ship an affected version, including @orpc/zod.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `@orpc/zod` | npm | All versions | 1.14.10 |
| `@orpc/zod` | npm | All versions | 1.14.10 |

## How do I fix CVE-2026-103918?

Upgrade @orpc/zod to 1.14.10 or later.

## Is CVE-2026-103918 being exploited?

There is no known exploitation of CVE-2026-103918 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-103918 and fix it if it is affected.

What it is: CVE-2026-103918 is a medium-severity unsafe deserialization vulnerability in middleapi orpc, published on 2 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-103918 in the wild and no public exploit code.

Affected packages and fixed versions:
- @orpc/zod (npm): affected all versions; fixed in 1.14.10
- @orpc/zod (npm): affected all versions; fixed in 1.14.10

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-103918/ (Markdown: https://insights.sbomify.com/CVE-2026-103918/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-103918
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-103918
- OSV: https://osv.dev/vulnerability/CVE-2026-103918

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-103918/
Summaries are generated and may contain mistakes; the official description above is the record.