EUVD-2026-81061
GHSA-2qg4-97v5-72x5
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Authorization logic validation
MITRE ATT&CK
1 technique across 1 tactic: Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | This is a genuine but access-gated authorization flaw, not a high-CVSS-but-low-risk paper cut. The vendor CVSS 4.0 vector (8.7, AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N) is internally consistent with the description: a network-reachable Feishu (Lark) card callback whose per-user allowlist check is missing, letting a low-privileged actor already present in an admitted chat dispatch agent commands. Because cc-connect bridges an AI/agent command surface to a chat platform, the VC:H/VI:H/VA:H rating is defensible - dispatched agent commands can plausibly read, modify, and disrupt whatever the agent is authorized to do on the backend. The critical limiter, reflected honestly as PR:L, is that the attacker must already be a member of an 'admitted' (allowlisted) chat; this is not an internet-wide unauthenticated primitive. No EPSS score, no CISA KEV entry, and no confirmed public exploit code are present in the input, so real-world exploitation pressure is currently unquantified. SSVC-style read: exploitation is 'none observed,' technical impact is 'total' (agent command execution), automatability is uncertain because it depends on the attacker first gaining chat membership. CWE-863 (Incorrect Authorization) is the correct root cause; the input 'Authentication Bypass' tag is loose - this bypasses per-user authorization inside an already-authenticated channel, not authentication itself. Net: a real priority for anyone actually running cc-connect, but the small deployment footprint and the chat-membership precondition keep aggregate risk moderate. |
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Alert meAnalysisAIv1 – Sep 16, 2026
Incorrect authorization in cc-connect through 1.5.0 allows an authenticated, low-privileged user who can trigger Feishu interactive card actions inside an admitted chat to dispatch agent commands, because the onCardAction handler never applies the per-user allowlist that the text message handler enforces. The result is an authorization bypass (CWE-863) rated CVSS 4.0 8.7 (AV:N/AC:L/AT:N/PR:L/UI:N, with high confidentiality, integrity and availability impact confined to the cc-connect scope), meaning a participant who should not be permitted to drive the agent can still do so remotely without user interaction. Exploitation is access-gated rather than open to the internet at large: the attacker must already belong to a Feishu chat that the deployment has admitted, and no public exploit code or confirmed active exploitation was identified at time of analysis, but the enabled agent-command path makes the impact substantive rather than theoretical.
RemediationAI
Patch status: no vendor-released fix version is identified in the available data, so the reference point is the upstream issue https://github.com/chenhg5/cc-connect/issues/1852 and the source at https://github.com/chenhg5/cc-connect/blob/v1.5.0/platform/feishu/feishu.go#L661-L680; operators should track the repository for a release newer than 1.5.0 and upgrade as soon as one is published, confirming the fix by testing that a non-allowlisted Feishu user cannot trigger agent commands via a card action. Until then, the most direct compensating control is to make the card action handler apply the same per-user allowlist as the text handler: either apply the upstream change or add the check locally in onCardAction before it dispatches to the agent, accepting the maintenance burden of a local fork. Alternatively, disable or stop registering interactive card callbacks for the bot (or restrict cards to non-actionable display-only types), which removes the vulnerable entry point entirely at the cost of losing card-driven workflows. Narrowing the blast radius by removing untrusted members from admitted Feishu chats and limiting bot installation to single-operator or tightly controlled chats is effective but only as strong as chat membership hygiene, and it leaves the authorization gap latent for any future member. Finally, because the handler forwards into the agent backend, constrain what the agent account can actually do (read-only or scoped tools, command allowlisting, audit logging of every card-triggered action) so an allowlist bypass cannot escalate into arbitrary command execution; these limits trade off agent usefulness for containment. The VulnCheck advisory at https://www.vulncheck.com/advisories/cc-connect-through-1.5.0-user-allowlist-bypass-via-feishu-card-actions should be monitored for updated fixed-version information.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in euvd
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
cc-connect (github.com/chenhg5/cc-connect) is a Go-based chat-to-agent connector that bridges messaging platforms, here Feishu/Lark, into an agent/command backend. Feishu supports interactive cards whose button/action interactions are delivered to the bot as card action callbacks, handled in platform/feishu/feishu.go around lines 661-680 (the onCardAction handler). The text-message code path in the same integration validates the acting user against a per-user allowlist before forwarding anything to the agent; the card action path omits that check, so the callback's declared identity is trusted and the command is dispatched. This is a textbook CWE-863 Incorrect Authorization instance: authentication of the platform callback (signature/event validation) is present, but authorization of the specific user is missing on a second, less-guarded entry point. The CVSS 4.0 vector shows AV:N, AC:L, AT:N, PR:L and UI:N, with VC/VI/VA all High while SC/SI/SA are None, i.e. the compromise is contained to the cc-connect component and the agent capabilities it exposes, and the attacker must already hold the low privilege of being able to interact with the bot in an admitted chat. Because both handlers converge on the same agent-command sink, the card action route effectively becomes a shadow interface that bypasses the deployment's user-level access policy.
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Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Primary rating from Vendor (VulnCheck) · only source for this CVE.
CVSS VectorVendor: VulnCheck
DescriptionCVE.org
cc-connect through 1.5.0 fails to enforce per-user allowlist filtering in the onCardAction handler for Feishu interactive card callbacks. Attackers can dispatch agent commands by triggering card actions in admitted chats, bypassing the per-user access controls that protect the text message handler.
Executive ViewAI
cc-connect versions through 1.5.0 contain a high-severity authorization bypass that allows any authenticated user in an admitted Feishu chat to dispatch agent commands via interactive card actions, bypassing the per-user allowlist enforced for text messages. This could enable unauthorized users to execute privileged agent operations, impacting confidentiality, integrity, and availability of the cc-connect deployment. Leadership should prioritize mitigation because the vulnerability is remotely exploitable by low-privileged chat participants, and no vendor patch is currently available.
No vendor-released patch identified at time of analysis. Interim mitigations: restrict Feishu chat admission to trusted users, monitor interactive card actions and agent command logs, disable agent command dispatch from card actions if feasible, and apply least privilege to cc-connect service accounts.
Threat Intelligence Overview
NVD
CVE.org
EPSS
Vulnrichment
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.
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Exploit-DB