CVE-2026-88257

See a problem?
Please try reporting it to the source first.

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

EEF-CVE-2026-88257
GHSA-mrg2-4747-fmpw

Published

2026-10-08T13:40:55Z

Modified

2026-10-09T02:49:26Z

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

083838eb8e17fe5f6fcaf761bdbe203110288b0b

Fixed

289dbdbad641943b29a3b8d1eb36506cc8cec10a

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"

Git / github.com/scriptkittyos/beam_mcp

Affected ranges

Type

GIT

Repo

https://github.com/scriptkittyos/beam_mcp

Events

Introduced

2add129e65d04759ce67c77520208b854c05dcee

Fixed

04548e143256729eb2cc99690861037c5372dbe8