CVE-2026-81835Public exploitNetwork attack vectorHinoki check available

Code execution via untrusted MCP server instructions

Published Aug 27, 2026 · Updated Aug 27, 2026

Code injection in Roo Code 3.51.0 through 3.51.1 allows remote authenticated users to execute code through a malicious MCP server. The fetch_instructions function in malicious_mcp_server.py supplies attacker-controlled MCP instructions that enter the model context without neutralization. A user must configure and interact with the malicious server; the injected instructions can invoke tools with the editor user's privileges.

CVSS severityUnavailable
Unscored
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Code injection in Roo Code 3.51.0 through 3.51.1 allows remote authenticated users to execute code through a malicious MCP server. The fetch_instructions function in malicious_mcp_server.py supplies attacker-controlled MCP instructions that enter the model context without neutralization. A user must configure and interact with the malicious server; the injected instructions can invoke tools with the editor user's privileges.

The record

CVE
CVE-2026-81835
Published
Aug 27, 2026
Updated
Aug 27, 2026
Vendor
Roo Code, Inc.
Product
Roo Code
Classifications
CWE-94, CWE-74, T1204
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 27, 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=3.51.0
  2. Affected versionversion=3.51.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Roo Code, Inc. · Roo Codeversion=3.51.0; version=3.51.1

Published CVSS scores

No CVSS assessment is available in this record.

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-94Improper Control of Generation of Code ('Code Injection')
CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
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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