CVE-2026-30856Public exploitNetwork attack vector

Tool execution hijacking via ambiguous MCP names

Published Mar 7, 2026 · Updated Mar 7, 2026

Tool execution hijacking in Tencent WeKnora before 0.3.0 allows remote authenticated users to redirect tool calls through a malicious MCP server. The MCP client joins sanitized service and tool names as mcp_{service}_{tool}, while ToolRegistry.RegisterTool silently overwrites an existing entry and returns unsanitized tool output to the LLM. Exploitation requires a user to register and invoke an attacker-controlled MCP service in the collision-producing order; success exposes prompts and context and can invoke tools with that user's privileges.

CVSS severity5.9
Medium
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Tool execution hijacking in Tencent WeKnora before 0.3.0 allows remote authenticated users to redirect tool calls through a malicious MCP server. The MCP client joins sanitized service and tool names as mcp_{service}_{tool}, while ToolRegistry.RegisterTool silently overwrites an existing entry and returns unsanitized tool output to the LLM. Exploitation requires a user to register and invoke an attacker-controlled MCP service in the collision-producing order; success exposes prompts and context and can invoke tools with that user's privileges.

The record

CVE
CVE-2026-30856
Published
Mar 7, 2026
Updated
Mar 7, 2026
Vendor
Tencent
Product
WeKnora
Classifications
CWE-706, T1204
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 7, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 7, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.3.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Tencent · WeKnoraversion=< 0.3.0

Published CVSS scores

5.9GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:L/A:L
7.6NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-706Use of Incorrectly-Resolved Name or Reference
T1204User Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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