EUVD-2026-58500
GHSA-4q4m-8h83-fcmr
Severity by source
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Network vector with high complexity for token extraction and phishing; PR:L for same-tenant session initiation; scope change captures downstream AI agent system impact.
Primary rating from Vendor (vulncheck).
CVSS VectorVendor: vulncheck
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Lifecycle Timeline
4DescriptionCVE.org
Budibase before 3.40.0 contains a cross-site request forgery vulnerability in the chat-link handoff endpoint that allows attackers to bind an external chat identity to a victim's account. Attackers can craft a phishing page that auto-submits a POST request with a leaked confirmation token to bind their chat identity to a victim user's account, enabling impersonation within agent operations and inheritance of victim permissions.
AnalysisAI
Cross-site request forgery in Budibase's AI chat-link handoff endpoint (GET/POST /api/chat-links/:instance/:token/handoff) permits a same-tenant attacker with low privileges to permanently bind their external chat identity (Slack, Discord, MS Teams, or Telegram) to any authenticated victim user's Budibase account. Because the confirmation token is rendered in plaintext inside the HTML page the victim views and the POST endpoint carries no CSRF protection or session binding, an attacker can extract the token from their own session initiation flow and embed it in a phishing page that auto-submits on load, hijacking the victim's globalUserId mapping. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | The following specific conditions must all be satisfied simultaneously: (1) The AI chat-link handoff feature must be enabled in the Budibase deployment and the affected endpoint /api/chat-links/:instance/:token/handoff must be reachable by the attacker. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 4.0 score of 8.7 (AV:N/AC:H/AT:P/PR:L/UI:P) is appropriate and consistent with the described attack surface. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker with low-level access to a shared Budibase tenant initiates a chat-link session for their own Slack identity, which generates a confirmationToken visible in the HTML of the confirmation page they receive. The attacker then constructs a phishing page containing a hidden form that auto-submits a POST to /api/chat-links/:instance/:token/handoff with the attacker's confirmationToken embedded, and sends the phishing link to a victim Budibase user who is currently logged in. … |
| Remediation | The upstream fix is available via GitHub Pull Request #19194 (https://github.com/Budibase/budibase/pull/19194) and commit 362e6c654fb4da6e123c734333da2d6cbdcdb7ef; however, a tagged released version containing the fix has not been independently confirmed from the provided package data - the package entry lists 'fixed in: None' while the CVE description references 3.40.0 as the threshold. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, disable or restrict access to the GET/POST /api/chat-links/:instance/:token/handoff endpoint using firewall rules, WAF policies, or application-level controls; simultaneously issue a security alert to all Budibase users warning against clicking untrusted chat-link URLs until a patch is available. …
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Same weakness CWE-352 – Cross-Site Request Forgery (CSRF)
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External POC / Exploit Code
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