CVE-2026-33143 in oneuptime
Summary
by MITRE • 03/20/2026
OneUptime is a solution for monitoring and managing online services. Prior to version 10.0.34, 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. This issue has been patched in version 10.0.34.
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Analysis
by VulDB Data Team • 03/27/2026
The vulnerability identified as CVE-2026-33143 affects OneUptime, a comprehensive monitoring and management solution for online services. This security flaw resides within the WhatsApp POST webhook handler located at the endpoint /notification/whatsapp/webhook. The issue represents a critical authentication bypass that undermines the integrity of the notification system by failing to validate incoming status update events from Meta's WhatsApp platform. The vulnerability specifically targets the absence of X-Hub-Signature-256 HMAC signature verification, which is a standard security mechanism designed to ensure that webhook payloads originate from legitimate sources and have not been tampered with during transmission.
The technical implementation of this flaw demonstrates a clear deviation from established security best practices and represents a weakness categorized under CWE-347, which deals with improper verification of cryptographic signatures. The codebase exhibits inconsistent security controls since it already implements proper signature verification for Slack webhooks, indicating that the development team was aware of the necessary security measures but failed to apply them uniformly across all supported platforms. This inconsistency creates a dangerous attack surface where malicious actors can exploit the missing validation mechanism to manipulate notification delivery status records.
The operational impact of this vulnerability extends beyond simple data manipulation to encompass potential security breaches and operational disruptions. Attackers can forge webhook payloads to suppress critical alerts, manipulate notification delivery status records, and corrupt audit trails that are essential for security monitoring and incident response. This capability allows adversaries to create false negatives in the monitoring system, potentially enabling them to conduct malicious activities without detection while simultaneously undermining the trustworthiness of the audit logs that organizations rely upon for compliance and forensic analysis. The vulnerability directly impacts the availability and integrity of the monitoring system's notification infrastructure.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1566.002, which involves social engineering through spearphishing with a link, and T1070.006, which covers manipulation of files and programs. The attack vector allows for persistent manipulation of the system's notification mechanisms, potentially enabling more sophisticated attacks that leverage the compromised communication channels. Organizations using OneUptime versions prior to 10.0.34 face significant risk of undetected malicious activity, as the forged webhook payloads can be used to mask actual security incidents while maintaining the appearance of normal system operation. The patch implemented in version 10.0.34 addresses this by restoring the X-Hub-Signature-256 HMAC verification mechanism, ensuring that only legitimate WhatsApp status update events can modify the notification delivery status records. This remediation restores the integrity of the audit trails and prevents unauthorized manipulation of the system's monitoring capabilities, aligning with security frameworks that emphasize the importance of input validation and authentication mechanisms in webhook processing systems.