CVE-2026-50132 in budibase
Summary
by MITRE • 06/27/2026
Budibase is an open-source low-code platform. Prior to 3.39.0, `GET /api/chat-links/:instance/:token/handoff` is a public endpoint (no auth required) that performs a permanent, state-changing operation: it binds an external chat identity (Slack/Discord/MS Teams) to an authenticated Budibase user account, with no consent UI and no CSRF protection. The session token in the URL is created by the attacker (from their own /link slash command) and embeds the attacker's externalUserId. When an authenticated Budibase victim visits the URL, their account is silently and permanently linked to the attacker's Slack/Discord identity. The server responds with "Authentication succeeded." — no indication of what was linked. This vulnerability is fixed in 3.39.0.
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Analysis
by VulDB Data Team • 06/27/2026
This vulnerability exists within Budibase's chat integration system where a critical authorization flaw allows attackers to silently link external chat identities to victim accounts without proper consent mechanisms or security protections. The affected endpoint GET /api/chat-links/:instance/:token/handoff operates as a public interface that accepts session tokens directly in the URL path, creating a dangerous attack vector where malicious actors can craft URLs with their own external user identifiers and trick authenticated users into visiting these links. The vulnerability stems from the absence of authentication checks, consent user interfaces, and CSRF protection mechanisms that should normally validate such sensitive operations before execution.
The technical implementation of this flaw demonstrates a classic case of insecure direct object reference combined with insufficient access control validation. When an authenticated victim visits the crafted URL, the system performs a permanent state change operation by binding the attacker's external chat identity to the victim's authenticated account without any user confirmation or awareness of the action being performed. The server response of "Authentication succeeded." provides no meaningful feedback about what specific linking operation occurred, effectively masking the security breach from both users and administrators. This design flaw allows attackers to establish persistent unauthorized access relationships between their chat identities and legitimate user accounts through social engineering or phishing techniques.
The operational impact of this vulnerability is severe as it enables attackers to gain unauthorized access to victim accounts through compromised chat integrations, potentially allowing them to monitor communications, execute commands, or escalate privileges within the Budibase platform. The lack of CSRF protection makes this attack particularly dangerous as it can be executed automatically when victims visit malicious websites or click on compromised links in chat applications. This vulnerability creates an attack surface that allows for account takeover scenarios and persistent unauthorized access that could go undetected for extended periods. The absence of any audit trail or user confirmation mechanism means that legitimate users may not realize their accounts have been compromised until they notice unusual activity or are explicitly notified by system administrators.
The fix implemented in version 3.39.0 addresses this vulnerability through proper authentication enforcement, mandatory consent mechanisms, and CSRF protection for the chat linking endpoint. This remediation aligns with security best practices outlined in CWE-639 which addresses authorization flaws, and follows ATT&CK techniques related to credential access and privilege escalation. Organizations should ensure all versions prior to 3.39.0 are updated immediately, implement monitoring for unusual chat integration activity, and review their access control policies to prevent similar vulnerabilities in other endpoints that handle user identity binding operations. The vulnerability demonstrates the critical importance of validating all user interactions with authentication systems and implementing proper security controls around state-changing operations in web applications.
This vulnerability represents a significant risk to organizations using Budibase's chat integration features and highlights the need for comprehensive security testing of all API endpoints, particularly those handling user identity management and authentication operations. The attack pattern described aligns with common social engineering techniques that exploit trust relationships between users and applications, making it essential for security teams to implement proper monitoring and incident response procedures for such scenarios.