Improper Input Validation in BeamMCP.Schema from ScriptKittyOS
CVE-2026-88257

5.3MEDIUM

Key Information:

Vendor

Scriptkittyos

Status
Beam Mcp
Vendor
CVE Published:
8 October 2026

What is CVE-2026-88257?

The improper input validation vulnerability in BeamMCP.Schema of ScriptKittyOS allows an MCP client to bypass the advertised input constraints of tools. It fails to enforce validations on nested object properties and array items, permitting the delivery of out-of-bounds values and undeclared keys to the dispatch function. When receiving such data, the host's response and handling determine the potential impact, presenting a risk for data integrity and application functionality.

Affected Version(s)

beam_mcp 0.1.0 < 0.10.1

beam_mcp 083838eb8e17fe5f6fcaf761bdbe203110288b0b < 289dbdbad641943b29a3b8d1eb36506cc8cec10a

References

https://github.com/ScriptKittyOS/beam_mcp/security/adviso...
relatedvendor-advisory
https://cna.erlef.org/cves/CVE-2026-88257.html
related
https://osv.dev/vulnerability/EEF-CVE-2026-88257
related

CVSS V4

Score:
5.3
Severity:
MEDIUM
Confidentiality:
None
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Ayla Croft / Script Kitty OS
Ayla Croft / Script Kitty OS
Ayla Croft / Script Kitty OS
Jonatan Männchen / EEF
.