CVE-2026-45018

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Source
https://cve.org/CVERecord?id=CVE-2026-45018
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-45018.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-45018
Aliases
Published
2026-08-25T19:18:46Z
Modified
2026-09-11T03:30:40Z
Severity
  • 9.8 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
Summary
Chainlit: Command injection via MCP stdio transport allows unauthenticated remote code execution
Details

Chainlit is a Python framework for building production-ready conversational AI applications. From 2.4.0rc0 until 2.12.0, Chainlit deployments with features.mcp.enabled set to true in .chainlit/config.toml expose the POST /mcp endpoint without requiring authentication. For stdio transport, the endpoint accepts a user-controlled fullCommand string. The validate_mcp_command() function in backend/chainlit/mcp.py checks only the executable name against config.features.mcp.stdio.allowed_executables and passes unchecked arguments to StdioServerParameters in backend/chainlit/server.py. Because npx supports the -c argument, an attacker can execute arbitrary shell commands with the privileges of the Chainlit process. If allowed_executables is unset, its None default is treated as allowing every executable. This issue is fixed in version 2.12.0.

Database specific 
{
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
        "CWE-78"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45018.json"
}
References

Affected packages

Git / github.com/chainlit/chainlit

Affected ranges

Type
GIT
Repo
https://github.com/chainlit/chainlit
Events
Introduced
dc13fc0c858ce65814b685ee39dc112a3bd38c87
Fixed
0565fd0eccb915fce159929598b053ed79f6e0c9
Database specific
Show details 
{
    "extracted_events": [
        {
            "introduced": "2.4.0rc0"
        },
        {
            "fixed": "2.12.0"
        }
    ],
    "source": [
        "AFFECTED_FIELD",
        "REFERENCES"
    ]
}

Affected versions

2.*
2.10.0
2.10.1
2.11.0
2.11.1
2.4.0
2.4.0rc0
2.4.1
2.4.2
2.4.201
2.4.3
2.4.301
2.4.302
2.4.400
2.5.5
2.6.0
2.6.1
2.6.2
2.6.3
2.6.4
2.6.5
2.6.6
2.6.7
2.6.8
2.6.9
2.7.0
2.7.1
2.7.1.1
2.7.2
2.8.0
2.8.1
2.8.2
2.8.3
2.8.4
2.8.5
2.9.0
2.9.1
2.9.2
2.9.3
2.9.4
2.9.5
2.9.6

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-45018.json"