Vulnerability report

Active exploitation observed Confirmed confidence Not in CISA KEV

CVE-2026-55786

flyto-core Flyto2 Core Unauthenticated OS command execution

Flyto2 / flyto-core

View live feed Monitor via API Watch CVE-2026-55786
Severity
CVSS 8.4 · High
Confidence
Confirmed
Exploit status
Observed in sensors
EPSS
—
First observed
13 Sep 2026
Last observed
19 Sep 2026

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2026-55786 is an unauthenticated vulnerability affecting Flyto2 flyto-core. The HTTP MCP endpoint (POST /mcp) in flyto-core accepts unauthenticated JSON-RPC tools/call requests and dispatches them to arbitrary...

Is it exploited?

Yes. Previdian sensors observed exploitation attempts with confirmed confidence.

Who is affected?

Flyto2 / flyto-core.

What should we do?

Patch immediately, validate internet-facing exposure, and monitor for matching requests.

Overview

flyto-core Flyto2 Core Unauthenticated OS command execution

The HTTP MCP endpoint (POST /mcp) in flyto-core accepts unauthenticated JSON-RPC tools/call requests and dispatches them to arbitrary registered modules, including sandbox.execute_shell, which passes attacker-controlled input directly to asyncio.create_subprocess_shell. An unauthenticated attacker can execute arbitrary OS commands as the flyto-core server process.

By default the server binds to 127.0.0.1, making this a High-severity local vulnerability (CVSS 8.4); if started with --host 0.0.0.0, it becomes remotely exploitable over the network. Dynamic reproduction confirmed command execution as root inside a Docker container without any Authorization header.

Published
—
Exploitation Reported
13 Sep 2026
Attack vector
Local
Complexity
Low
Privileges
None
User interaction
None

CVE References

  • CVE Record CVE.org · CVE Record https://www.cve.org/CVERecord?id=CVE-2026-55786

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

Previdian

Recorded 13 Sep 2026

Previdian independently recorded this as exploited after first seeing it in honeypot sensors.

Active exploitation observed

Previdian sensor

First observed 13 Sep 2026

Previdian first observed exploitation attempts targeting this vulnerability in our honeypot sensors.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

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Source Added
Previdian First 2026-09-14 07:22 UTC

Operational indicators for this CVE are listed under Detection.

Sensor telemetry

First-party evidence of exploitation activity

Previdian sensors recorded exploitation attempts targeting this vulnerability. The cards and chart show volume, unique attackers, and daily activity.

194

Attempts observed

175

Unique attacker IPs

5

Attacker countries

BE · IN · SG · TW · US

9

Sensors observed

CVE-2026-55786 exploitation attempts over the last 8 days

Daily events observed by Previdian sensors

Updated 19 Sep 2026

0
7
3
1
1
110
35
37
12 Sep 13 Sep 14 Sep 15 Sep 16 Sep 17 Sep 18 Sep 19 Sep

First observed 13 Sep 2026 · Last observed 19 Sep 2026

Pro adds sensor region and window summaries. Enterprise adds raw IPs, paths, User-Agents, and payloads.

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Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
1
32
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Scanner coverage

No scanner integrations recorded yet.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

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Attacker IP Indicators

Attacker IP indicators observed · available in Pro and Enterprise.

Sensor-derived attacker IP indicators are available to Pro and Enterprise accounts under Detection and through the Pro API.

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Risk and context

Severity, weaknesses, and research context

CVSS v3.1

8.4 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

—

Timeline

From disclosure to observed exploitation

  1. 08:32 UTC

    Indicators of compromise added (175)

    Indicators of compromise recorded

  2. 08:32 UTC

    Observed by Previdian sensors

    Evidence-backed exploitation signal

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2026-55786

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2026-55786",
  "confidence": "Confirmed",
  "cvss_score": 8.4,
  "cvss_estimated": false,
  "epss_score": null,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": true
  },
  "sensor_telemetry": { "attempts": 194, "sensors": 9 }
}