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PatchSiren cyber security CVE debrief

CVE-2026-81735 bytedance CVE debrief

The CVE-2026-81735 vulnerability affects the UI-TARS-desktop's mcp-http-server package, which had a default listen address of '::' binding Streamable HTTP and SSE MCP transports to every interface without authentication. The @agent-infra/mcp-server-commands and @agent-infra/mcp-server-filesystem entry points did not require credentials, exposing a run_command tool that could run arbitrary commands as the user running the server. Users and administrators should prioritize patching and compensating controls to prevent unauthenticated arbitrary command execution. Evidence is based on official CVE Program and NVD records, as well as source references. The fix involves updating to commit c2ad42e3eb9b27830db41a3e6f51ca7179d9b168 or later. Affected deployments require immediate attention due to critical severity.

Vendor
bytedance
Product
UI-TARS-desktop
CVSS
CRITICAL 10
CISA KEV
Not listed in stored evidence
Original CVE published
2026-08-27
Original CVE updated
2026-08-31
Advisory published
2026-08-27
Advisory updated
2026-08-31

Who should care

Users and administrators of UI-TARS-desktop, especially those with exposed mcp-http-server instances, should prioritize patching and implementing compensating controls to prevent unauthenticated arbitrary command execution.

Technical summary

The mcp-http-server package in UI-TARS-desktop had a default listen address of '::' which bound the Streamable HTTP and SSE MCP transports to every interface without authentication. The @agent-infra/mcp-server-commands and @agent-infra/mcp-server-filesystem entry points did not require credentials. The commands server exposed a run_command tool that could run arbitrary commands as the user running the server.

Defensive priority

Immediate attention is required due to the critical severity and potential for unauthenticated arbitrary command execution.

Recommended defensive actions

  • Inventory and verify the presence of affected mcp-http-server package versions.
  • Apply the fix by updating to the commit c2ad42e3eb9b27830db41a3e6f51ca7179d9b168 or later.
  • Implement compensating controls such as network access restrictions and monitoring.
  • Retest and verify the fix in a controlled environment.
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.
  • Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.
  • Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed.

Evidence notes

The mcp-http-server package in UI-TARS-desktop had a default listen address of '::' which bound the Streamable HTTP and SSE MCP transports to every interface without authentication. The @agent-infra/mcp-server-commands and @agent-infra/mcp-server-filesystem entry points did not require credentials. The commands server exposed a run_command tool that could run arbitrary commands as the user running the server. Evidence is based on official CVE Program and NVD records, as well as source references from [email protected].

Sources and references

Verified primary and authoritative sources

  • CVE-2026-81735 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-81735

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-81735 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-81735

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.