Vulnerability report

Active exploitation observed Confirmed confidence Not in CISA KEV

CVE-2025-8943

Flowise Remote Code Execution

Flowise · affected before 3.0.1

Watch CVE-2025-8943 Browse KEV feed
Severity
CVSS 9.8 · Critical
Confidence
Confirmed
Exploit status
Observed in sensors
EPSS
74.8%
First observed
25 Jun 2026
Last observed
09 Oct 2026

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2025-8943 is an unauthenticated vulnerability affecting Flowise. The Custom MCPs feature is designed to execute OS commands, for instance, using tools like `npx` to spin up local MCP Servers. However, Flowise's...

Is it exploited?

Yes. Previdian sensors observed exploitation attempts with confirmed confidence.

Who is affected?

Flowise affected before 3.0.1.

What should we do?

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

Overview

Flowise Remote Code Execution

The Custom MCPs feature is designed to execute OS commands, for instance, using tools like `npx` to spin up local MCP Servers. However, Flowise's inherent authentication and authorization model is minimal and lacks role-based access controls (RBAC).

Furthermore, in Flowise versions before 3.0.1 the default installation operates without authentication unless explicitly configured. This combination allows unauthenticated network attackers to execute unsandboxed OS commands.

— Affected
— flowise
Before 3.0.1
View vendor advisory (opens in new tab)
Published
14 Aug 2025
Exploited Since
25 Jun 2026
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

nuclei_scanner

CVE References

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 10 Jul 2026

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

Active exploitation observed

Previdian sensor

First observed 10 Jul 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.

Learn about Pro API access
Source Added
Previdian Sensors First 2026-08-05 08:45 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.

529

Attempts observed

213

Unique attacker IPs

21

Attacker countries

AU · BG · BN · CA · CH · CN · DE · ES · FR · GB · HK · IL · IN · IR · JP · NL · PL · SG · TH · US · VN

10

Sensors observed

CVE-2025-8943 exploitation attempts over the last 91 days

Daily events observed by Previdian sensors

Updated 09 Oct 2026

3
0
0
0
0
12
3
3
2
0
2
1
3
9
0
0
0
3
0
2
3
0
0
0
0
1
0
0
1
2
1
1
2
5
6
1
2
6
2
1
2
5
3
1
2
2
2
4
8
4
5
13
3
4
3
0
2
2
9
7
8
7
2
1
2
1
2
11
21
20
3
11
2
2
2
1
8
11
2
29
1
1
16
29
26
26
28
26
39
28
5
11 Jul 30 Jul 18 Aug 6 Sep 9 Oct

First observed 25 Jun 2026 · Last observed 09 Oct 2026

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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
5
40
8

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

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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Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Nuclei https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2025/CVE-2025-8943.yaml 01 Jun 2026

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

9.8 Critical

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

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

EPSS

74.8%

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 Missing Authorization CWE-862

Recent mention · Github Advisory Database (NPM)

[flowise-components] Flowise: CVE-2025-8943 Patch Bypass: npm_config_yes bypasses MCP environment variable blocklist (Unauthenticated RCE)

Summary The mitigation shipped for CVE-2025-8943 blocks the -y and --yes flags on npx to stop auto-installation of arbitrary packages. That flag filter works. The environment-variable check in the same patch denies only four variable names by exact string match, and npm reads...

Read full advisory

All Mentions

Recent mention · Github Advisory Database (NPM)

[flowise-components] Flowise: CVE-2025-8943 Patch Bypass: npm_config_yes bypasses MCP environment variable blocklist (Unauthenticated RCE)

Github Advisory Database (NPM) · 04 Aug 2026

Summary The mitigation shipped for CVE-2025-8943 blocks the -y and --yes flags on npx to stop auto-installation of arbitrary packages. That flag filter works. The environment-variable check in the same patch denies only four variable names by exact string match, and npm reads its configuration directly from npm_config_* environment variables. Setting npm_config_yes=true reproduces the --yes behaviour the flag filter is meant to prevent, so npx auto-installs and executes the named package. The mitigation is fully bypassed. This works with the MCP security check enabled...

Recent mention · Github Advisory Database (NPM)

[flowise] Flowise: CVE-2025-8943 Patch Bypass: npm_config_yes bypasses MCP environment variable blocklist (Unauthenticated RCE)

Github Advisory Database (NPM) · 04 Aug 2026

Summary The mitigation shipped for CVE-2025-8943 blocks the -y and --yes flags on npx to stop auto-installation of arbitrary packages. That flag filter works. The environment-variable check in the same patch denies only four variable names by exact string match, and npm reads its configuration directly from npm_config_* environment variables. Setting npm_config_yes=true reproduces the --yes behaviour the flag filter is meant to prevent, so npx auto-installs and executes the named package. The mitigation is fully bypassed. This works with the MCP security check enabled...

Potential Proof of Concepts

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

Flowise < 3.0.1 - Remote Command Execution

nuclei · Created Unknown

Timeline

From disclosure to observed exploitation

  1. 15:38 UTC

    Observed by Previdian sensors

    Evidence-backed exploitation signal

  2. 23:45 UTC

    Indicators of compromise added (215)

    Indicators of compromise recorded

  3. 14:21 UTC

    Public PoC available

    Public proof-of-concept code published

  4. 15:34 UTC

    Nuclei template available

    Scanner coverage available

  5. 09:54 UTC

    CVE published

    Vulnerability disclosed publicly

  6. 13:30 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-2025-8943

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2025-8943",
  "confidence": "Confirmed",
  "cvss_score": 9.8,
  "cvss_estimated": false,
  "epss_score": 0.74787,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": true
  },
  "sensor_telemetry": { "attempts": 529, "sensors": 10 }
}