@orpc/zod: Prototype injection in smart coercion

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-103918: 0.25% estimated exploitation activity in the next 30 days; percentile 16.19 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary ZodSmartCoercionPlugin and experimentalZodSmartCoercionPlugin mishandle object keys that name Object.prototype members. Both coerce request input before validation, so any client that can reach a procedure whose input schema contains an object or a record can: 1. replace the prototype of the coerced input object, and 2. make a request fail with an unhandled TypeError by sending a key such as constructor. This is the same class of bug as GHSA-4h5r-cv8j-4456 in @orpc/json-schema, in a different package. This is not global prototype pollution The global Object.prototype is never modified. No shared or global state is written, so other objects in the process, other requests, and other users are not affected. What changes is the prototype of one object: the value the coercer returns for the request that carried the payload. That object is passed on to validation and to the procedure handler, then discarded when the request ends. An ordinary {} created anywhere else in the…

Published by the source

5 Oct 2026, 17:32 UTC

Last modified by the source

5 Oct 2026, 17:45 UTC

Source last checked

26 Oct 2026, 13:06 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-gcgf-fh7c-8gf2

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-gcgf-fh7c-8gf2

3. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-gcgf-fh7c-8gf2

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# Patch Next advisory brief: CVE-2026-103918

Advisory: @orpc/zod: Prototype injection in smart coercion
IDs: CVE-2026-103918, GHSA-gcgf-fh7c-8gf2
Record: https://patchnext.com/advisories/cve-2026-103918 (revision 3, source checked 26 Oct 2026, 13:06 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @orpc/zod 1.14.10. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @orpc/zod: affected < 1.14.10; fixed in 1.14.10

## Suggested inspection (read-only)
- `npm ls @orpc/zod --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on @orpc/zod.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-gcgf-fh7c-8gf2 (GitHub-reviewed advisory GHSA-gcgf-fh7c-8gf2 lists affected ranges: npm @orpc/zod >=0 <1.14.10)
- Verified: https://osv.dev/vulnerability/GHSA-gcgf-fh7c-8gf2 (OSV record GHSA-gcgf-fh7c-8gf2 lists affected ranges: npm @orpc/zod >=0 <1.14.10 (fixed))

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