CVE-2026-79660 in Ech0
Summary
by MITRE • 08/25/2026
Ech0 versions before 4.7.3 expose guest commenter email addresses through public API endpoints due to improper JSON serialization tags on the Comment model. Unauthenticated attackers can harvest all commenter emails by calling the /api/comments and /api/comments/public endpoints without authentication.
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Analysis
by VulDB Data Team • 08/25/2026
The vulnerability identified in Ech0 versions prior to 4.7.3 represents a critical information disclosure flaw rooted in misconfigured data serialization within the application's backend logic. Specifically, the Comment model utilizes improper JSON serialization tags that fail to restrict access to sensitive fields during API response generation. This configuration error results in the unintended exposure of guest commenter email addresses through publicly accessible endpoints. The root cause lies in the absence of proper field-level security controls or visibility modifiers on the data structure returned by the application, allowing internal attributes intended for administrative use only to be serialized and transmitted to unauthenticated clients.
From a technical perspective, this flaw allows any external actor with network access to the target system to retrieve sensitive personal information without needing valid credentials. By invoking the /api/comments or /api/comments/public endpoints, an attacker can harvest a comprehensive list of email addresses associated with user comments on the platform. This type of vulnerability is classically categorized under CWE-200: Information Exposure and more specifically aligns with CWE-789: Uncontrolled Data Structure Serialization when the serialization mechanism fails to enforce access controls on specific data members. The lack of authentication requirements for these endpoints exacerbates the severity, as it removes any barrier preventing automated scraping tools from collecting large volumes of personally identifiable information in a short timeframe.
The operational impact of this vulnerability extends beyond simple privacy violations. Harvested email addresses can be leveraged by malicious actors to conduct targeted phishing campaigns, credential stuffing attacks, or spam distribution efforts against the affected user base. This compromises the confidentiality and integrity of user data, potentially leading to regulatory non-compliance with standards such as GDPR or CCPA due to the unauthorized exposure of personal information. Furthermore, the availability of these emails can facilitate social engineering attacks that may lead to account compromise for individual users if they reuse passwords across services. The trust in the platform's security posture is significantly eroded when basic data protection mechanisms are found to be ineffective against unauthenticated requests.
To mitigate this vulnerability, immediate remediation efforts should focus on correcting the JSON serialization configuration within the Comment model. Developers must ensure that sensitive fields such as email addresses are explicitly excluded from public API responses or protected by appropriate access control checks before serialization occurs. Implementing strict input validation and output encoding practices will help prevent unintended data leakage. Additionally, applying principle of least privilege to API endpoints is crucial; if an endpoint does not require user context for its primary function, it should not expose sensitive attributes unless explicitly authorized. Upgrading Ech0 to version 4.7.3 or later resolves this issue by addressing the serialization tags and enforcing proper access controls on comment data exposure. Regular security audits and static code analysis tools configured to detect improper serialization patterns can help prevent similar issues in future development cycles, aligning with ATT&CK technique T1589: Gather Victim Identity Information for reconnaissance prevention through proactive defense strategies.