CVE-2026-88257

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Source
https://cve.org/CVERecord?id=CVE-2026-88257
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-88257.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-88257
Aliases
Published
2026-10-08T13:40:55Z
Modified
2026-10-28T02:31:02Z
Severity
  • 5.3 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N CVSS Calculator
Summary
beam_mcp: nested tool argument constraints advertised but not enforced
Details

Improper Input Validation vulnerability in BeamMCP.Schema in ScriptKittyOS beam_mcp allows an MCP client to reach a tool's dispatch function with arguments that violate the input schema the server advertised. BeamMCP.Schema.validate/2 checked type, required, additionalProperties, enum and numeric bounds on the top-level arguments object only. Constraints inside nested objects and on array items (items, minItems, maxItems, minLength, maxLength, pattern, nested required, enum and additionalProperties: false) were advertised by tools/list and never checked at tools/call or prompts/get, and keywords outside the enforced subset (oneOf, anyOf, $ref) were advertised and ignored.

A host whose dispatch code relies on the schema it declared receives values the schema forbids, such as an out-of-range number or an undeclared key inside a nested object. What the host does with such a value decides the impact.

This issue affects beam_mcp: from 0.1.0 before 0.10.1.

Database specific 
{
    "cna_assigner":  "EEF",
    "cwe_ids":  [
        "CWE-20"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/88xxx/CVE-2026-88257.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":  [
        {
            "range":  [
                {
                    "introduced":  "0.1.0"
                },
                {
                    "fixed":  "0.10.1"
                }
            ],
            "source":  "AFFECTED_FIELD",
            "strategy":  "StandardRange"
        },
        {
            "range":  [
                {
                    "fixed":  "083838eb8e17fe5f6fcaf761bdbe203110288b0b"
                }
            ],
            "source":  "REFERENCES_COMMIT"
        },
        {
            "range":  [
                {
                    "fixed":  "289dbdbad641943b29a3b8d1eb36506cc8cec10a"
                }
            ],
            "source":  "REFERENCES_COMMIT"
        }
    ]
}

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-2026-88257.json"