CVE-2026-77360

oRPC is an tool that helps build APIs that are end-to-end type-safe and adhere to OpenAPI standards. Prior to 1.14.8, the @orpc/server CORS plugin in packages/server/src/plugins/cors.ts copies a client's incoming Vary request header into the response instead of controlling Vary as a response-only header and using Origin for request-origin variation. In deployments behind a shared cache, CDN, or reverse proxy that keys responses using Vary, a client can inject arbitrary variation values, pollute cache keys, and cause inconsistent CORS enforcement for other clients. Default non-cached configurations have no established direct confidentiality, integrity, or availability impact. This issue is fixed in version 1.14.8.

oRPC is an tool that helps build APIs that are end-to-end type-safe and adhere to OpenAPI standards. Prior to 1.14.8, the @orpc/server CORS plugin in packages/server/src/plugins/cors.ts copies a client's incoming Vary request header into the response instead of controlling Vary as a response-only header and using Origin for request-origin variation. In deployments behind a shared cache, CDN, or reverse proxy that keys responses using Vary, a client can inject arbitrary variation values, pollute cache keys, and cause inconsistent CORS enforcement for other clients. Default non-cached configurations have no established direct confidentiality, integrity, or availability impact. This issue is fixed in version 1.14.8.

### 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.

### 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.