GHSA-j9v4-rhgr-4m5f
oRPC: Vary Header Injection in CORS Plugin leading to potential Cache/CORS Bypass
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| npm | @orpc/server | < 1.14.8 | 1.14.8 |
Details
As written in the advisory (Markdown source, shown as plain text).
### Summary
A flaw in the CORS plugin allowed the incoming request's `Vary` header to be reflected into the response, letting a client influence a header that should be controlled solely by the server.
### Details
The CORS plugin previously copied the request's `Vary` header directly onto the response instead of treating `Vary` as a response-only header. Because `Vary` tells downstream caches and proxies how to key their cached responses, this allowed a client to inject arbitrary values into the response's `Vary` header, potentially distorting cache-key behavior in shared caches/CDNs sitting in front of an oRPC server and leading to inconsistent CORS enforcement for other clients.
Practical impact is limited to deployments where a shared cache or reverse proxy keys on the `Vary` header; the real-world effect depends on the caching layer's configuration.
### Impact
May cause cache key pollution and inconsistent CORS enforcement in setups that rely on shared/edge caches keying on `Vary`. No direct confidentiality, integrity, or availability impact in default (non-cached) configurations.
### Resolution
Update `@orpc/server` (and any other `@orpc/*` packages bundling the CORS plugin) to `1.14.8`. The CORS plugin now derives `Vary` exclusively from the response, appending `Origin` and preserving existing values instead of reflecting request headers.
References
External links from the advisory. They lead to third-party sites.
- https://github.com/middleapi/orpc/security/advisories/GHSA-j9v4-rhgr-4m5f
- https://nvd.nist.gov/vuln/detail/CVE-2026-77360
- https://github.com/middleapi/orpc/issues/1661
- https://github.com/middleapi/orpc/pull/1662
- https://github.com/middleapi/orpc/commit/daabded122a89d323357c4c401e879701864cb2f
- https://github.com/middleapi/orpc
- https://github.com/middleapi/orpc/releases/tag/v1.14.8