diff --git a/CHANGELOG.md b/CHANGELOG.md
index e0ac96377633..e67639b987e9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -23,6 +23,7 @@ Docs: https://docs.openclaw.ai
 
 ### Fixes
 
+- **Microsoft Teams Graph response bounds:** cap successful file-upload and chat JSON reads so oversized Microsoft Graph responses cannot be buffered without limit. (#97784) Thanks @Alix-007.
 - **Packaged speech runtime:** stop treating package-backed `speech-core` as a bundled plugin sidecar, restoring TTS startup in npm installs while release checks keep true activation-bypassing facades package-complete. (#89899, #89425) Thanks @zhangguiping-xydt.
 - **Codex app-server protocol:** require app-server 0.142 or newer, remove pre-0.142 wire-shape compatibility, and teach Codex to retrieve deferred native `spawn_agent` through `tool_search` so native subagent task mirroring works on search-capable models. (#101221)
 - **Android hardware keyboard chat:** send with unmodified Enter on physical keyboards while preserving Shift+Enter and other modified Enter combinations for multiline input. (#101239) Thanks @3ninyt3nin-creator.
diff --git a/extensions/msteams/src/graph-upload.test.ts b/extensions/msteams/src/graph-upload.test.ts
index 8ea828d26455..f00cee480c57 100644
--- a/extensions/msteams/src/graph-upload.test.ts
+++ b/extensions/msteams/src/graph-upload.test.ts
@@ -1,6 +1,6 @@
 // Msteams tests cover graph upload plugin behavior.
-import { withFetchPreconnect } from "openclaw/plugin-sdk/test-env";
-import { describe, expect, it, vi } from "vitest";
+import { withFetchPreconnect, withServer } from "openclaw/plugin-sdk/test-env";
+import { afterEach, describe, expect, it, vi } from "vitest";
 import { buildTeamsFileInfoCard } from "./graph-chat.js";
 import { resolveGraphChatId, uploadToOneDrive, uploadToSharePoint } from "./graph-upload.js";
 
@@ -249,6 +249,60 @@ describe("resolveGraphChatId", () => {
   });
 });
 
+describe("graph upload response limits", () => {
+  const tokenProvider = {
+    getAccessToken: vi.fn(async () => "graph-token"),
+  };
+
+  afterEach(() => {
+    vi.restoreAllMocks();
+    vi.unstubAllGlobals();
+  });
+
+  it("rejects an oversized upload response from a real loopback server", async () => {
+    await withServer(
+      (_req, res) => {
+        res.writeHead(200, { "content-type": "application/json" });
+        const chunk = Buffer.alloc(64 * 1024, 0x20);
+        let remaining = 257; // >16 MiB when combined with the JSON prefix.
+        res.write(
+          '{"id":"item-big","webUrl":"https://example.com/big","name":"big.txt","padding":"',
+        );
+        const writeNext = () => {
+          if (remaining <= 0) {
+            res.end('"}');
+            return;
+          }
+          remaining -= 1;
+          if (res.write(chunk)) {
+            setImmediate(writeNext);
+          } else {
+            res.once("drain", writeNext);
+          }
+        };
+        writeNext();
+      },
+      async (baseUrl) => {
+        const realFetch = globalThis.fetch.bind(globalThis);
+        vi.stubGlobal(
+          "fetch",
+          withFetchPreconnect(async (input: RequestInfo | URL, init?: RequestInit) => {
+            const url = new URL(input instanceof Request ? input.url : String(input));
+            const loopback = new URL(`${url.pathname}${url.search}`, baseUrl);
+            return realFetch(loopback, init);
+          }),
+        );
+
+        await expect(
+          uploadToOneDrive({ buffer: Buffer.from("x"), filename: "big.txt", tokenProvider }),
+        ).rejects.toThrow(
+          "msteams.graph-upload.uploadOneDriveFile: JSON response exceeds 16777216 bytes",
+        );
+      },
+    );
+  });
+});
+
 describe("buildTeamsFileInfoCard", () => {
   it("extracts a unique id from quoted etags and lowercases file extensions", () => {
     expect(
diff --git a/extensions/msteams/src/graph-upload.ts b/extensions/msteams/src/graph-upload.ts
index 42fc8d2a9b75..f313160dbe0d 100644
--- a/extensions/msteams/src/graph-upload.ts
+++ b/extensions/msteams/src/graph-upload.ts
@@ -9,6 +9,7 @@
  * - Getting chat members for per-user sharing
  */
 
+import { readProviderJsonResponse } from "openclaw/plugin-sdk/provider-http";
 import type { MSTeamsAccessTokenProvider } from "./attachments/types.js";
 import { createMSTeamsHttpError } from "./http-error.js";
 import { buildUserAgent } from "./user-agent.js";
@@ -54,11 +55,11 @@ export async function uploadToOneDrive(params: {
     throw await createMSTeamsHttpError(res, "OneDrive upload failed");
   }
 
-  const data = (await res.json()) as {
+  const data = await readProviderJsonResponse<{
     id?: string;
     webUrl?: string;
     name?: string;
-  };
+  }>(res, "msteams.graph-upload.uploadOneDriveFile");
 
   if (!data.id || !data.webUrl || !data.name) {
     throw new Error("OneDrive upload response missing required fields");
@@ -106,9 +107,9 @@ async function createSharingLink(params: {
     throw await createMSTeamsHttpError(res, "Create sharing link failed");
   }
 
-  const data = (await res.json()) as {
+  const data = await readProviderJsonResponse<{
     link?: { webUrl?: string };
-  };
+  }>(res, "msteams.graph-upload.createOneDriveSharingLink");
 
   if (!data.link?.webUrl) {
     throw new Error("Create sharing link response missing webUrl");
@@ -200,11 +201,11 @@ export async function uploadToSharePoint(params: {
     throw await createMSTeamsHttpError(res, "SharePoint upload failed");
   }
 
-  const data = (await res.json()) as {
+  const data = await readProviderJsonResponse<{
     id?: string;
     webUrl?: string;
     name?: string;
-  };
+  }>(res, "msteams.graph-upload.uploadSharePointFile");
 
   if (!data.id || !data.webUrl || !data.name) {
     throw new Error("SharePoint upload response missing required fields");
@@ -260,11 +261,11 @@ export async function getDriveItemProperties(params: {
     throw await createMSTeamsHttpError(res, "Get driveItem properties failed");
   }
 
-  const data = (await res.json()) as {
+  const data = await readProviderJsonResponse<{
     eTag?: string;
     webDavUrl?: string;
     name?: string;
-  };
+  }>(res, "msteams.graph-upload.getDriveItemProperties");
 
   if (!data.eTag || !data.webDavUrl || !data.name) {
     throw new Error("DriveItem response missing required properties (eTag, webDavUrl, or name)");
@@ -331,9 +332,9 @@ export async function resolveGraphChatId(params: {
     return null;
   }
 
-  const data = (await res.json()) as {
+  const data = await readProviderJsonResponse<{
     value?: Array<{ id?: string }>;
-  };
+  }>(res, "msteams.graph-upload.getOneOnOneChatId");
 
   const chats = data.value ?? [];
 
@@ -371,12 +372,12 @@ async function getChatMembers(params: {
     throw await createMSTeamsHttpError(res, "Get chat members failed");
   }
 
-  const data = (await res.json()) as {
+  const data = await readProviderJsonResponse<{
     value?: Array<{
       userId?: string;
       displayName?: string;
     }>;
-  };
+  }>(res, "msteams.graph-upload.getChatMembers");
 
   return (data.value ?? [])
     .map((m) => ({
@@ -435,9 +436,9 @@ async function createSharePointSharingLink(params: {
     throw await createMSTeamsHttpError(res, "Create SharePoint sharing link failed");
   }
 
-  const data = (await res.json()) as {
+  const data = await readProviderJsonResponse<{
     link?: { webUrl?: string };
-  };
+  }>(res, "msteams.graph-upload.createSharePointSharingLink");
 
   if (!data.link?.webUrl) {
     throw new Error("Create SharePoint sharing link response missing webUrl");