CVE-2026-45555Public exploit

Arbitrary code execution via untrusted analyzer loading

Published May 29, 2026 · Updated May 29, 2026

Code injection in Roslyn CodeLens MCP Server before 1.17.0 allows attackers to execute arbitrary code through a malicious project. AnalyzerRunner.GetAnalyzers unconditionally collects project AnalyzerReferences, and GetAnalyzerDiagnosticsAsync loads and invokes each DLL in the server process. Exploitation requires the victim to open an attacker-supplied solution and call get_diagnostics, after which code runs with the server process's OS privileges.

CVSS severity7.8
High
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code injection in Roslyn CodeLens MCP Server before 1.17.0 allows attackers to execute arbitrary code through a malicious project. AnalyzerRunner.GetAnalyzers unconditionally collects project AnalyzerReferences, and GetAnalyzerDiagnosticsAsync loads and invokes each DLL in the server process. Exploitation requires the victim to open an attacker-supplied solution and call get_diagnostics, after which code runs with the server process's OS privileges.

The record

CVE
CVE-2026-45555
Published
May 29, 2026
Updated
May 29, 2026
Vendor
Marcel Roozekrans
Product
Roslyn CodeLens MCP Server
Classifications
CWE-94, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 29, 2026CVE publishedPublication date reported by the CVE source.
  2. May 29, 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=>= 0.0.9, < 1.17.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Marcel Roozekrans · Roslyn CodeLens MCP Serverversion=>= 0.0.9, < 1.17.0

Published CVSS scores

7.8GitHub, Inc.CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

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.

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No observations available

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

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
T1204.002Malicious File

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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