CVE-2026-101050 in Heym
Summary
by MITRE • 09/27/2026
Heym before 0.0.53 fails to verify the X-Telegram-Bot-Api-Secret-Token header on Telegram webhook endpoints when credential_id is absent or secret_token is empty. Remote unauthenticated attackers can post forged Telegram updates to trigger workflows with the owner's configured credentials and execute actions on attacker-supplied input.
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Analysis
by VulDB Data Team • 09/27/2026
The vulnerability identified in Heym versions prior to 0.0.53 represents a critical authentication bypass within its integration of Telegram webhook endpoints. The core technical flaw lies in the application logic governing the verification of incoming requests from the Telegram Bot API. Specifically, when an administrator configures a bot without providing a secret_token or leaves this field empty, and simultaneously relies on credential_id for identification, Heym fails to enforce strict validation of the X-Telegram-Bot-Api-Secret-Token header. This oversight creates a significant gap in access control, as the system does not adequately verify that incoming webhook payloads originate from Telegram's official servers when the secondary token-based verification mechanism is absent or nullified.
From an operational perspective, this flaw allows remote unauthenticated attackers to forge valid-looking Telegram update requests and submit them directly to Heym’s webhook endpoints. By crafting malicious JSON payloads that mimic legitimate bot updates, adversaries can trick the application into processing these inputs as authentic commands from users who have interacted with the bot. This effectively bypasses any intended authentication or authorization checks tied to specific user identities within the workflow engine. The attacker gains the ability to trigger automated workflows and execute actions defined by the system owner using their configured credentials, but with input data controlled entirely by the adversary rather than a genuine end-user.
The impact of this vulnerability is severe, as it enables unauthorized execution of arbitrary code or administrative actions depending on how Heym processes these forged updates. Attackers can exploit this to perform unintended operations such as sending messages, modifying configurations, accessing sensitive data stored in workflow variables, or executing system commands if the workflows involve shell interactions. This constitutes a direct compromise of integrity and potentially confidentiality within the automation environment. The ability to inject arbitrary input into automated processes undermines trust in the entire bot infrastructure, allowing for potential denial-of-service through resource exhaustion or more sophisticated attacks like server-side request forgery if subsequent steps involve external API calls based on attacker-supplied data.
This issue aligns with CWE-287 Improper Authentication and CWE-918 Server-Side Request Forgery (SSRF) depending on the specific workflow actions triggered by the forged updates. In terms of MITRE ATT&CK, this vulnerability facilitates Initial Access via Valid Accounts or Service Accounts if the bot credentials are compromised through other means, but more directly it represents an Authentication Bypass that allows for subsequent Execution and Command and Control activities within the internal network context where Heym operates. The lack of robust input validation against forged external service headers is a common pitfall in webhook implementations that must be addressed to ensure secure integration with third-party platforms like Telegram.
To mitigate this risk, administrators should immediately upgrade Heym to version 0.0.53 or later, which includes the necessary fixes for header verification logic. For environments where upgrading is not immediately feasible, a temporary workaround involves ensuring that every bot configuration explicitly sets a strong, random secret_token in the webhook settings within the Telegram Bot API interface and configuring Heym to require this token for all incoming requests. Additionally, implementing network-level controls such as IP whitelisting for Telegram’s official server addresses can provide an additional layer of defense by restricting which sources are allowed to send data to the webhook endpoint. Regular security audits of automation workflows should also be conducted to identify any other potential injection points or logic flaws that could be exploited through similar mechanisms in connected services.