diff --git a/src/infra/http-body.test.ts b/src/infra/http-body.test.ts
index 81a2575cf8c7..5e1f43b944da 100644
--- a/src/infra/http-body.test.ts
+++ b/src/infra/http-body.test.ts
@@ -1,6 +1,7 @@
 import { EventEmitter } from "node:events";
 import type { IncomingMessage } from "node:http";
 import { beforeEach, describe, expect, it, vi } from "vitest";
+import { MAX_TIMER_TIMEOUT_MS } from "../shared/number-coercion.js";
 import { createMockServerResponse } from "../test-utils/mock-http-response.js";
 import {
   installRequestBodyLimitGuard,
@@ -8,6 +9,7 @@ import {
   type RequestBodyLimitErrorCode,
   readJsonBodyWithLimit,
   readRequestBodyWithLimit,
+  testApi,
 } from "./http-body.js";
 
 type MockIncomingMessage = IncomingMessage & {
@@ -254,6 +256,18 @@ describe("http body limits", () => {
     expect(req["__unhandledDestroyError"]).toBeUndefined();
   });
 
+  it("does not overflow oversized request body timeouts into immediate failures", async () => {
+    expect(
+      testApi.resolveRequestBodyLimitValues({
+        maxBytes: 128,
+        timeoutMs: Number.MAX_SAFE_INTEGER,
+      }),
+    ).toEqual({
+      maxBytes: 128,
+      timeoutMs: MAX_TIMER_TIMEOUT_MS,
+    });
+  });
+
   it("guard clamps invalid maxBytes to one byte", async () => {
     const { res } = await expectGuardPayloadTooLarge({
       chunks: ["ab"],
diff --git a/src/infra/http-body.ts b/src/infra/http-body.ts
index d7c14e8c69de..f89eb844a060 100644
--- a/src/infra/http-body.ts
+++ b/src/infra/http-body.ts
@@ -1,5 +1,6 @@
 import type { IncomingMessage, ServerResponse } from "node:http";
 import { clearTimeout as clearNodeTimeout, setTimeout as setNodeTimeout } from "node:timers";
+import { resolveTimerTimeoutMs } from "../shared/number-coercion.js";
 import { formatErrorMessage } from "./errors.js";
 import { parseStrictNonNegativeInteger } from "./parse-finite-number.js";
 
@@ -101,12 +102,15 @@ function resolveRequestBodyLimitValues(options: {
     ? Math.max(1, Math.floor(options.maxBytes))
     : 1;
   const timeoutMs =
-    typeof options.timeoutMs === "number" && Number.isFinite(options.timeoutMs)
-      ? Math.max(1, Math.floor(options.timeoutMs))
-      : DEFAULT_WEBHOOK_BODY_TIMEOUT_MS;
+    options.timeoutMs === undefined
+      ? DEFAULT_WEBHOOK_BODY_TIMEOUT_MS
+      : resolveTimerTimeoutMs(options.timeoutMs, DEFAULT_WEBHOOK_BODY_TIMEOUT_MS);
   return { maxBytes, timeoutMs };
 }
 
+export const testApi = { resolveRequestBodyLimitValues };
+export { testApi as __test__ };
+
 function advanceRequestBodyChunk(
   chunk: Buffer | string,
   totalBytes: number,