Which versions are affected?

CVE-2026-55786 affects Flytohub flyto-core. Reported affected version: >= 2.26.2, < 2.26.4.

How should organizations remediate it?

Prioritize immediate patching and validate internet-facing exposure. Monitor for matching exploitation attempts in your environment.

No. CVE-2026-55786 is not currently listed in CISA KEV.

CVE-2026-55786 Exploitation Attempts Observed — flyto-core

Q: Have exploitation attempts been observed for CVE-2026-55786?

Yes. Previdian sensors observed exploitation attempts targeting this vulnerability. Confidence is confirmed.

Q: What exploitation activity has Previdian observed?

Previdian sensors have observed 283 exploitation attempts, 242 unique attacker IPs, and 12 countries targeting CVE-2026-55786. First observed Sep 13, 2026; last observed Sep 25, 2026.

Q: How should organizations remediate it?

Prioritize immediate patching and validate internet-facing exposure. Monitor for matching exploitation attempts in your environment.

Q: Is it in CISA KEV?

No. CVE-2026-55786 is not currently listed in CISA KEV.

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 Flytohub flyto-core. Flyto2 Core is an execution kernel for automation and AI-agent workflows.

Have exploitation attempts been observed?

Yes. Previdian sensors have observed 283 exploitation attempts, 242 unique attacker IPs, and 12 countries targeting CVE-2026-55786. First observed Sep 13, 2026; last observed Sep 25, 2026. Confidence is confirmed.

Who is affected?

Flytohub / flyto-core >= 2.26.2, < 2.26.4.

What should we do?

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

Overview

Flyto2 Core is an execution kernel for automation and AI-agent workflows

Flyto2 Core is an execution kernel for automation and AI-agent workflows. From 2.26.2 until 2.26.4, the HTTP MCP POST /mcp route accepts unauthenticated JSON-RPC tools/call requests and forwards execute_module arguments to the module registry without the require_auth dependency used by the REST execution routes. An unauthenticated caller can select sandbox.execute_shell and supply its command parameter, which reaches asyncio.create_subprocess_shell with the privileges of the flyto-core server process.

The endpoint is reachable locally under the default loopback binding and becomes network reachable when an operator binds the server to a non-loopback interface, allowing arbitrary OS command execution and potential full host compromise. This issue is fixed in version 2.26.4.

Vendor Product Affected Status

flytohub Affected

flyto-core

>= 2.26.2, < 2.26.4

Affected

Published: 14 Oct 2026
Exploitation Attempts 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
https://github.com/flytohub/flyto-core/security/advisories/GHSA-h9f9-h6gm-wc85 github.com · CVE Record https://github.com/flytohub/flyto-core/security/advisories/GHSA-h9f9-...
https://github.com/flytohub/flyto-core/commit/db7f116b1d3c5dcf94aded00d14118f81f3e225e github.com · CVE Record https://github.com/flytohub/flyto-core/commit/db7f116b1d3c5dcf94aded0...
https://github.com/flytohub/flyto-core/releases/tag/v2.26.4 github.com · CVE Record https://github.com/flytohub/flyto-core/releases/tag/v2.26.4

Exploitation evidence

Evidence of exploitation attempts

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

Exploitation Attempts Observed in the Wild

Previdian

Recorded 13 Sep 2026

Previdian sensors observed exploitation attempts targeting this vulnerability.

Exploitation Attempts Observed

Previdian sensor

First observed 13 Sep 2026

Previdian sensors observed exploitation attempts targeting this vulnerability.

Proof of concept available

GitHub Advisory Database

Recorded 14 Oct 2026

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

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

Learn about Pro API access

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

Operational indicators for this CVE are listed under Detection.

Sensor telemetry

Previdian Sensor Observations

Previdian sensor observations are exploitation attempts targeting this vulnerability. They do not show that the target was vulnerable or that the attempt succeeded. The cards and chart show volume, unique attackers, and daily activity.

283

Attempts observed

242

Unique attacker IPs

12

Attacker countries

AR · BE · BR · CA · DE · HK · IN · JP · NL · SG · TW · US

14

Sensors observed

CVE-2026-55786 exploitation attempts over the last 55 days

Daily events observed by Previdian sensors

Updated 05 Nov 2026

0

7

3

1

110

35

37

4

22

7

13

23

20

0

12 Sep 23 Sep 4 Oct 15 Oct 5 Nov

First observed 13 Sep 2026 · Last observed 25 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.

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.

Learn about virtual patches →

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

Potential damage if exploited. Separate from whether attackers are using it.

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

EPSS

0.4%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Missing Authentication for Critical Function CWE-306 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') CWE-78

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

https://github.com/flytohub/flyto-core/security/advisories/GHSA-h9f9-h6gm-wc85

ghsa · Created Unknown · AI assessment 99%

flyto-core has Unauthenticated Command Execution via HTTP MCP `execute_module`

Timeline

From disclosure to observed exploitation attempts

14 Oct 2026
18:40 UTC

Public PoC available

Public proof-of-concept code published
14 Oct 2026
18:14 UTC

CVE published

Vulnerability disclosed publicly
13 Sep 2026
08:32 UTC

Indicators of compromise added (242)

Indicators of compromise recorded
13 Sep 2026
08:32 UTC

Observed by Previdian sensors

Previdian sensors observed exploitation attempts targeting this vulnerability.
17 Jun 2026
14:40 UTC

CVE ID reserved

Identifier reserved by the CNA

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

Sample API response

{
  "cve_id": "CVE-2026-55786",
  "confidence": "Confirmed",
  "cvss_score": 8.4,
  "cvss_estimated": false,
  "epss_score": 0.0041,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": true
  },
  "sensor_telemetry": { "attempts": 283, "sensors": 14 }
}