EUVD-2026-42765
GHSA-8f88-w9gq-227v
Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/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-accessible MQTT service exploited by low-privilege connected client via client_id manipulation; no scope change; low and symmetric C/I/A impact consistent with CVSS 4.0 VC:L/VI:L/VA:L.
Primary rating from Vendor (VulDB).
CVSS VectorVendor: VulDB
Lifecycle Timeline
4DescriptionCVE.org
A weakness has been identified in Sipeed PicoClaw up to 0.2.9. Affected by this issue is some unknown functionality of the file pkg/channels/mqtt/mqtt.go of the component MQTT Channel Handler. This manipulation of the argument client_id causes incorrect authorization. The attack is possible to be carried out remotely. The exploit has been made available to the public and could be used for attacks. The reported GitHub issue was closed automatically due to inactivity.
AnalysisAI
Incorrect authorization in Sipeed PicoClaw's MQTT Channel Handler (pkg/channels/mqtt/mqtt.go) through version 0.2.9 allows remote low-privileged attackers to bypass access controls by manipulating the client_id argument, enabling unauthorized access to MQTT channels belonging to other clients. A public proof-of-concept exploit exists via the referenced GitHub issue, elevating practical risk beyond the moderate CVSS 4.0 score of 5.3. No vendor patch has been released - the upstream GitHub issue was closed automatically due to inactivity - leaving affected deployments without an official remediation path.
Technical ContextAI
The vulnerability resides in pkg/channels/mqtt/mqtt.go, the MQTT Channel Handler of Sipeed PicoClaw (CPE: cpe:2.3:a:sipeed:picoclaw:*:*:*:*:*:*:*:*), an IoT platform developed by Sipeed, a Chinese hardware vendor known for RISC-V and embedded systems. MQTT (Message Queuing Telemetry Transport) is a lightweight publish/subscribe protocol widely used in IoT deployments, where the client_id is a broker-assigned or client-supplied identifier used to distinguish sessions and enforce per-client authorization. CWE-863 (Incorrect Authorization) indicates the handler fails to properly bind the client_id presented at connection or channel-access time to the authenticated session's verified identity or permissions, allowing an attacker to supply an arbitrary or spoofed client_id to assume another client's channel access rights without re-authenticating as that client.
RemediationAI
No vendor-released patch has been identified at time of analysis - the associated GitHub issue (https://github.com/sipeed/picoclaw/issues/3068) was closed automatically due to inactivity rather than through a code fix, and no patched release is reflected in the CPE data. Operators should monitor the upstream repository at https://github.com/sipeed/picoclaw/ for any future releases addressing this issue. As a compensating control, restrict network access to the MQTT broker using firewall rules or network ACLs to allow only explicitly trusted clients to reach the broker on ports 1883 (plain MQTT) or 8883 (MQTT over TLS), which prevents untrusted network peers from exploiting the flaw - note this does not protect against insider or co-tenant threats. Implement strict broker-side authorization (e.g., via an MQTT broker ACL layer such as Mosquitto's auth plugin) that independently validates client permissions at the broker level rather than relying on PicoClaw's channel handler logic. Placing the service behind a VPN or isolating it on a private network segment reduces exposure further, though this does not eliminate the vulnerability for connected clients. Consider forking and patching the mqtt.go handler to validate that the supplied client_id matches the authenticated session identity before granting channel access.
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Same weakness CWE-863 – Incorrect Authorization
View allSame technique Authentication Bypass
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External POC / Exploit Code
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