diff --git a/src/server/cors/origins.ts b/src/server/cors/origins.ts
index dfd0b407c5..a354cccb5e 100644
--- a/src/server/cors/origins.ts
+++ b/src/server/cors/origins.ts
@@ -144,6 +144,26 @@ export function getCorsStatus(): CorsStatus {
  * compression middleware only appends it conditionally, so shared caches can't
  * otherwise reliably tell compressed vs uncompressed variants apart.
  */
+function requestCarriesTokenOrPreflight(request: Request): boolean {
+  // Preflight (OPTIONS) never carries the Authorization / x-api-key header, so it
+  // must be allowed through — the actual request that follows is re-evaluated by
+  // this same check and only gets the permissive Origin if it presents a token.
+  if (request.method === "OPTIONS") return true;
+  if (
+    request.headers.get("authorization") ||
+    request.headers.get("x-api-key") ||
+    request.headers.get("x-goog-api-key")
+  ) {
+    return true;
+  }
+  // A dashboard session cookie is a credential too (#5242 browser/Electron
+  // clients). auth_token is HttpOnly + SameSite, so a cross-site attacker page
+  // cannot get it auto-attached — only a truly credential-less request (the
+  // GHSA-7px7 anonymous case on a keyless install) falls through to fail-closed.
+  const cookie = request.headers.get("cookie");
+  return Boolean(cookie && /(?:^|;\s*)auth_token=/.test(cookie));
+}
+
 export function applyCorsHeaders(
   response: Response,
   request: Request,
@@ -151,7 +171,15 @@ export function applyCorsHeaders(
 ): void {
   const requestOrigin = request.headers.get("origin");
   let allowed = resolveAllowedOrigin(requestOrigin);
-  if (allowed === null && relaxForTokenAuth) {
+  if (allowed === null && relaxForTokenAuth && requestCarriesTokenOrPreflight(request)) {
+    // GHSA-7px7-29v2-m97p: the permissive Origin echo is only safe on the
+    // assumption that these routes are token-authenticated (browsers never
+    // auto-attach Authorization/x-api-key). On a keyless install that assumption
+    // breaks — an anonymous cross-origin page would be echoed its own Origin and
+    // could read the response. Only relax for a request that actually carries a
+    // credential, plus CORS preflights (OPTIONS never carries the header — the
+    // real request that follows is re-checked), so authenticated browser/Electron
+    // clients (#5242) keep working while credential-less cross-origin reads do not.
     allowed = requestOrigin && requestOrigin.length > 0 ? requestOrigin : "*";
   }
   if (allowed !== null) {
diff --git a/tests/unit/cors/origins.test.ts b/tests/unit/cors/origins.test.ts
index 00950aa097..7d8ecd42ec 100644
--- a/tests/unit/cors/origins.test.ts
+++ b/tests/unit/cors/origins.test.ts
@@ -129,12 +129,12 @@ describe("cors/origins.applyCorsHeaders", () => {
     assert.match(res.headers.get("Vary") || "", /Origin/);
   });
 
-  it("CLIENT_API: echoes arbitrary Origin (+Vary) when no allowlist matches (relaxForTokenAuth)", () => {
+  it("CLIENT_API: echoes arbitrary Origin (+Vary) for a token-carrying request (relaxForTokenAuth)", () => {
     // Token-authenticated /v1/* surface (issue #5242): no allowlist, arbitrary
     // origin → echo it back so browser/Electron renderers can read the body.
     const res = NextResponse.json({ ok: true });
     const req = new Request("https://server.example.com/api/v1/models", {
-      headers: { Origin: "http://localhost" },
+      headers: { Origin: "http://localhost", Authorization: "Bearer omr_test_key" },
     });
     applyCorsHeaders(res, req, true);
     assert.equal(res.headers.get("Access-Control-Allow-Origin"), "http://localhost");
@@ -143,14 +143,40 @@ describe("cors/origins.applyCorsHeaders", () => {
     assert.equal(res.headers.get("Access-Control-Allow-Credentials"), null);
   });
 
-  it("CLIENT_API: returns '*' when no Origin header is present (relaxForTokenAuth)", () => {
+  it("CLIENT_API: returns '*' when no Origin header is present for a token-carrying request", () => {
     const res = NextResponse.json({ ok: true });
-    const req = new Request("https://server.example.com/api/v1/models");
+    const req = new Request("https://server.example.com/api/v1/models", {
+      headers: { "x-api-key": "omr_test_key" },
+    });
     applyCorsHeaders(res, req, true);
     assert.equal(res.headers.get("Access-Control-Allow-Origin"), "*");
     assert.equal(res.headers.get("Access-Control-Allow-Credentials"), null);
   });
 
+  it("CLIENT_API: does NOT echo the Origin for a credential-less cross-origin request (GHSA-7px7)", () => {
+    // A keyless install serves /v1 anonymously; echoing the Origin to a
+    // credential-less cross-origin page would let any visited page drive the
+    // gateway. Only token-carrying requests get the permissive echo.
+    const res = NextResponse.json({ ok: true });
+    const req = new Request("https://server.example.com/api/v1/models", {
+      headers: { Origin: "https://evil.example" },
+    });
+    applyCorsHeaders(res, req, true);
+    assert.equal(res.headers.get("Access-Control-Allow-Origin"), null);
+  });
+
+  it("CLIENT_API: a CORS preflight (OPTIONS) is still allowed through (relaxForTokenAuth)", () => {
+    // Preflight never carries the auth header; blocking it would break the
+    // credentialed request that follows, so OPTIONS keeps the permissive echo.
+    const res = new Response(null, { status: 204 });
+    const req = new Request("https://server.example.com/api/v1/models", {
+      method: "OPTIONS",
+      headers: { Origin: "http://localhost" },
+    });
+    applyCorsHeaders(res, req, true);
+    assert.equal(res.headers.get("Access-Control-Allow-Origin"), "http://localhost");
+  });
+
   it("MANAGEMENT: stays fail-closed for arbitrary Origin with no allowlist (relax off)", () => {
     const res = NextResponse.json({ ok: true });
     const req = new Request("https://server.example.com/api/keys", {
@@ -213,7 +239,11 @@ describe("cors/origins.applyCorsHeaders", () => {
 
   it("CLIENT_API: appends Vary: Accept-Encoding even without an Origin header (#6737)", () => {
     const res = NextResponse.json({ ok: true });
-    const req = new Request("https://server.example.com/api/v1/models");
+    // Token-carrying request (post-GHSA-7px7 the permissive echo requires a
+    // credential); this test's point is the Vary: Accept-Encoding stamp.
+    const req = new Request("https://server.example.com/api/v1/models", {
+      headers: { "x-api-key": "omr_test_key" },
+    });
     applyCorsHeaders(res, req, true);
     assert.equal(res.headers.get("Access-Control-Allow-Origin"), "*");
     assert.match(res.headers.get("Vary") || "", /Accept-Encoding/);