diff --git a/CHANGELOG.md b/CHANGELOG.md
index a485bd6b8..82d108e31 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -22,6 +22,12 @@ Code v99.99.999
 
 ## Unreleased
 
+### Fixed
+
+- When proxying, cookies were being decoded and re-encoded, which could cause
+  issues for applications that encode differently. Cookies are now passed
+  through unchanged (aside from stripping out code-server's session token).
+
 ## [4.131.0](https://github.com/coder/code-server/releases/tag/v4.131.0) - 2026-07-30
 
 Code v1.131.0
diff --git a/src/node/proxy.ts b/src/node/proxy.ts
index 8282729cc..2d9056996 100644
--- a/src/node/proxy.ts
+++ b/src/node/proxy.ts
@@ -20,17 +20,31 @@ proxy.on("error", (error, _, res) => {
   }
 })
 
+function identity<T>(val: T): T {
+  return val
+}
+
 // Strip the code-server cookie if it exists to avoid transmitting the cookie
 // to potentially malicious local ports.
 proxy.on("proxyReq", (preq, req) => {
-  const cookieSessionName = getCookieSessionName((req as Request).args["cookie-suffix"])
-  preq.setHeader(
-    "Cookie",
-    cookie.stringifyCookie({
-      ...(req as Request).cookies,
-      [cookieSessionName]: undefined,
-    }),
-  )
+  if (req.headers.cookie) {
+    const cookieSessionName = getCookieSessionName((req as Request).args["cookie-suffix"])
+    // Encoding and decoding are no-ops; we just want to remove the token
+    // without changing anything else about the cookies because not all
+    // applications encode/decode the same way `cookie` here does.
+    preq.setHeader(
+      "Cookie",
+      cookie.stringifyCookie(
+        {
+          ...cookie.parseCookie(req.headers.cookie, { decode: identity }),
+          [cookieSessionName]: undefined,
+        },
+        {
+          encode: identity,
+        },
+      ),
+    )
+  }
 })
 
 // Intercept the response to rewrite absolute redirects against the base path.
diff --git a/test/unit/node/proxy.test.ts b/test/unit/node/proxy.test.ts
index 94945cb94..4c3320a07 100644
--- a/test/unit/node/proxy.test.ts
+++ b/test/unit/node/proxy.test.ts
@@ -298,25 +298,44 @@ describe("proxy", () => {
     process.env.HASHED_PASSWORD = token
     codeServer = await integration.setup(["--auth=password"])
 
-    // Set up a listener that just prints the cookies it got.
     e.get("/wsup/cookies", (req, res) => {
       res.writeHead(HttpCode.Ok, { "Content-Type": "text/plain" })
       res.end(req.headers.cookie)
     })
 
-    // Send the token along with other cookies which should be preserved.
-    // Encode one to make sure they are being re-encoded properly.
-    const value = "hello=there"
-    const encodedValue = encodeURIComponent(value)
-    const resp = await codeServer.fetch(proxyPath + "/cookies", {
-      headers: {
-        cookie: `cookie1=${encodedValue}; code-server-session=${token}; cookie2=hello;`,
-      },
+    const cookies = [
+      "cookie2=hello",
+      // Cookies should pass through unchanged, neither encoded nor decoded.
+      `cookie1=${encodeURIComponent("hello=there")}`,
+      "cookie3=foo|bar",
+      `cookie4=${encodeURIComponent("foo|bar")}`,
+      `cookie5=${encodeURIComponent("bar;baz")}`,
+    ]
+
+    // Test each slot to ensure the token is found anywhere.
+    for (let i = 0; i <= cookies.length; ++i) {
+      const left = cookies.slice(0, i)
+      const right = cookies.slice(i)
+      const resp = await codeServer.fetch(proxyPath + "/cookies", {
+        headers: {
+          cookie: [...left, `code-server-session=${token}`, ...right].join("; "),
+        },
+      })
+      expect(resp.status).toBe(200)
+      expect(await resp.text()).toBe(cookies.join("; "))
+    }
+  })
+
+  it("should proxy when no cookies", async () => {
+    codeServer = await integration.setup(["--auth=none"])
+
+    e.get("/wsup/cookies", (req, res) => {
+      res.writeHead(HttpCode.Ok, { "Content-Type": "text/plain" })
+      res.end(req.headers.cookie || "no cookies")
     })
 
-    // The proxied listener should not have printed the code-server token.
+    const resp = await codeServer.fetch(proxyPath + "/cookies")
     expect(resp.status).toBe(200)
-    const text = await resp.text()
-    expect(text).toBe(`cookie1=${encodedValue}; cookie2=hello`)
+    expect(await resp.text()).toBe("no cookies")
   })
 })