Summary
oRPC: Vary Header Injection in CORS Plugin leading to potential Cache/CORS Bypass
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.
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.
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.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2026-77360? CVE-2026-77360 is a medium-severity security vulnerability in @orpc/server (npm), affecting versions <= 1.14.7. It is fixed in 1.14.8.
- Which versions of @orpc/server are affected by CVE-2026-77360? @orpc/server (npm) versions <= 1.14.7 is affected.
- Is there a fix for CVE-2026-77360? Yes. CVE-2026-77360 is fixed in 1.14.8. Upgrade to this version or later.
- Is CVE-2026-77360 exploitable, and should I be worried? Whether CVE-2026-77360 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-77360 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-77360? Upgrade
@orpc/serverto 1.14.8 or later.