@@ -157,7 +157,7 @@
     "tinyglobby": "^0.2.16",
     "tsconfck": "^3.1.6",
     "typescript": "^6.0.3",
-    "ufo": "^1.6.3",
+    "ufo": "^1.6.4",
     "ultrahtml": "^1.6.0",
     "uncrypto": "^0.1.3",
     "unctx": "^2.5.0",
 
@@ -33,6 +33,8 @@ export const redirect: RouteRuleCtor<"redirect"> = ((m) =>
           throw new HTTPError({ status: 400 });
         }
         targetPath = withoutBase(targetPath, strpBase);
+      } else if (targetPath.startsWith("//")) {
+        targetPath = targetPath.replace(/^\/+/, "/");
       }
       target = joinURL(target.slice(0, -3), targetPath);
     } else if (event.url.search) {
@@ -56,6 +58,8 @@ export const proxy: RouteRuleCtor<"proxy"> = ((m) =>
           throw new HTTPError({ status: 400 });
         }
         targetPath = withoutBase(targetPath, strpBase);
+      } else if (targetPath.startsWith("//")) {
+        targetPath = targetPath.replace(/^\/+/, "/");
       }
       target = joinURL(target.slice(0, -3), targetPath);
     } else if (event.url.search) {
 
@@ -111,13 +111,15 @@ export default defineConfig({
       redirect: { to: "https://nitro.build/", status: 308 },
     },
     "/rules/redirect/wildcard/**": { redirect: "https://nitro.build/**" },
+    "/rules/redirect/legacy/**": { redirect: "/**" },
     "/rules/nested/**": { redirect: "/base", headers: { "x-test": "test" } },
     "/rules/nested/override": { redirect: { to: "/other" } },
     "/rules/_/noncached/cached": { swr: true },
     "/rules/_/noncached/**": { swr: false, cache: false, isr: false },
     "/rules/_/cached/noncached": { cache: false, swr: false, isr: false },
     "/rules/_/cached/**": { swr: true },
     "/api/proxy/**": { proxy: "/api/echo" },
+    "/rules/proxy/legacy/**": { proxy: "/api/wildcard/**" },
     "/cdn/**": { proxy: "https://cdn.jsdelivr.net/**" },
     "/rules/basic-auth/**": {
       basicAuth: { username: "admin", password: "secret", realm: "Secure Area" },
 
@@ -42,6 +42,7 @@ describe("nitro:preset:netlify", async () => {
 
         expect(redirects).toMatchInlineSnapshot(`
           "/rules/nested/override	/other	302
+          /rules/redirect/legacy/*	/:splat	302
           /rules/redirect/wildcard/*	https://nitro.build/:splat	302
           /rules/redirect/obj	https://nitro.build/	301
           /rules/ba-redirect/*	/base	302
 
@@ -81,6 +81,13 @@ describe("nitro:preset:vercel:web", async () => {
                 "src": "/rules/redirect/wildcard/(.*)",
                 "status": 307,
               },
+              {
+                "headers": {
+                  "Location": "/$1",
+                },
+                "src": "/rules/redirect/legacy/(.*)",
+                "status": 307,
+              },
               {
                 "headers": {
                   "Location": "/other",
 
@@ -317,6 +317,15 @@ export function testNitro(
     });
     expect(wildcard.status).toBe(307);
     expect(wildcard.headers.location).toBe("https://nitro.build/nuxt");
+
+    // Regression test for GHSA-9phm-9p8f-hw5m: a leading `//` after the
+    // wildcard prefix must not be forwarded as a protocol-relative URL.
+    const legacy = await callHandler({
+      url: "/rules/redirect/legacy//evil.com",
+    });
+    expect(legacy.status).toBe(307);
+    expect(legacy.headers.location).not.toMatch(/^\/\//);
+    expect(legacy.headers.location).toBe("/evil.com");
   });
 
   it("binary response", async () => {
@@ -569,6 +578,15 @@ export function testNitro(
     }
   });
 
+  it("runtime proxy collapses leading slashes after wildcard prefix", async () => {
+    // Regression test for GHSA-9phm-9p8f-hw5m: a leading `//` after the
+    // wildcard prefix must not be forwarded verbatim to the upstream.
+    const { data } = await callHandler({
+      url: "/rules/proxy/legacy//evil.com",
+    });
+    expect(data).toBe("evil.com");
+  });
+
   it("external proxy", async () => {
     const { data, headers, status } = await callHandler({
       url: "/cdn/npm/bootstrap@5.3.8/dist/js/bootstrap.min.js",
Original file line number	Diff line number	Diff line change
`@@ -33,6 +33,8 @@ export const redirect: RouteRuleCtor<"redirect"> = ((m) =>`
`33`	`33`	`throw new HTTPError({ status: 400 });`
`34`	`34`	`}`
`35`	`35`	`targetPath = withoutBase(targetPath, strpBase);`
	`36`	`+ } else if (targetPath.startsWith("//")) {`
	`37`	`+ targetPath = targetPath.replace(/^\/+/, "/");`
`36`	`38`	`}`
`37`	`39`	`target = joinURL(target.slice(0, -3), targetPath);`
`38`	`40`	`} else if (event.url.search) {`
`@@ -56,6 +58,8 @@ export const proxy: RouteRuleCtor<"proxy"> = ((m) =>`
`56`	`58`	`throw new HTTPError({ status: 400 });`
`57`	`59`	`}`
`58`	`60`	`targetPath = withoutBase(targetPath, strpBase);`
	`61`	`+ } else if (targetPath.startsWith("//")) {`
	`62`	`+ targetPath = targetPath.replace(/^\/+/, "/");`
`59`	`63`	`}`
`60`	`64`	`target = joinURL(target.slice(0, -3), targetPath);`
`61`	`65`	`} else if (event.url.search) {`