CVE-2026-104634

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Source
https://cve.org/CVERecord?id=CVE-2026-104634
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-104634.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-104634
Aliases
Published
2026-10-08T13:41:05Z
Modified
2026-10-10T02:47:22Z
Severity
  • 2.3 (Low) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N CVSS Calculator
Summary
beam_mcp: JSON boolean and null tool arguments reach dispatch as strings
Details

Incorrect Type Conversion or Cast vulnerability in BeamMCP.Server in ScriptKittyOS beam_mcp allows an MCP client's JSON true, false and null tool arguments to reach the host's dispatch function as the strings "true", "false" and "nil". After BeamMCP.Schema.validate/2 accepted a value as a boolean, normalize_arguments/2 passed every argument through to_json_value/1, whose atom clause converts true, false and nil to strings. A string is truthy in Elixir, so a host that tests a boolean argument, for example if args.dry_run, takes the opposite branch for false, and a guard such as confirm: false reads as set.

The client controls the argument and could send true directly, so the practical impact is limited to hosts whose behaviour on false differs from their behaviour on true, and to any policy layer in front of the server that permits false but refuses true. The same normalisation applies to prompts/get arguments, which exist from 0.5.0.

This issue affects beam_mcp: from 0.1.0 before 0.10.1.

Database specific 
{
    "cna_assigner":  "EEF",
    "cwe_ids":  [
        "CWE-704"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/104xxx/CVE-2026-104634.json"
}
References

Affected packages

Git / github.com/scriptkittyos/beam_mcp

Affected ranges

Type
GIT
Repo
https://github.com/scriptkittyos/beam_mcp
Events
Introduced
2add129e65d04759ce67c77520208b854c05dcee
Fixed
04548e143256729eb2cc99690861037c5372dbe8
Fixed
083838eb8e17fe5f6fcaf761bdbe203110288b0b
Fixed
289dbdbad641943b29a3b8d1eb36506cc8cec10a
Database specific
Show details 
{
    "extracted_events":  [
        {
            "introduced":  "0.1.0"
        },
        {
            "fixed":  "0.10.1"
        }
    ],
    "source":  [
        "DESCRIPTION",
        "REFERENCES"
    ]
}

Affected versions

v0.*
v0.1.0
v0.10.0
v0.2.0
v0.3.0
v0.3.1
v0.4.0
v0.5.0
v0.6.0
v0.7.0
v0.8.0
v0.9.0

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-104634.json"