KEV Intelligence

Vulnerability report

Active exploitation observed Confirmed confidence Not in CISA KEV

CVE-2026-5027

langflow Path Traversal Arbitrary File Write

langflow-ai / langflow · 0

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Severity
CVSS 8.8 · High
Confidence
Confirmed
Exploit status
Observed in sensors
EPSS
31.4%
First observed
10 Jul 2026
Last observed
18 Aug 2026

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2026-5027 is a vulnerability affecting langflow-ai langflow. The 'POST /api/v2/files' endpoint does not sanitize the 'filename' parameter from the multipart form data, allowing an attacker to write files to...

Is it exploited?

Yes. KEV Intelligence sensors observed exploitation attempts with confirmed confidence.

Who is affected?

langflow-ai / langflow 0.

What should we do?

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

Overview

langflow Path Traversal Arbitrary File Write

The 'POST /api/v2/files' endpoint does not sanitize the 'filename' parameter from the multipart form data, allowing an attacker to write files to arbitrary locations on the filesystem using path traversal sequences ('../').

Vendor Product Affected Status
langflow-ai langflow 0 Affected
Published
27 Mar 2026
Exploitation Reported
10 Jun 2026
Attack vector
Remote
Complexity
Low
Privileges
Low
User interaction
None

Tags

nuclei_scanner

CVE References

Exploitation evidence

Why KEV Intelligence 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

TheHackerNews

Recorded 10 Jun 2026

Independent exploitation attestation added to the KEV Intelligence record.

Active exploitation observed

KEV Intelligence sensor

First observed 10 Jul 2026

First-party sensor telemetry confirms matching exploitation attempts.

Proof of concept available

GitHub

Recorded 02 Apr 2026

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

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

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Source Added
TheHackerNews First 2026-06-10 16:20 UTC
BleepingComputer 2026-06-10 22:20 UTC
The Shadowserver 2026-07-10 00:00 UTC
KEV Intelligence 2026-07-10 15:15 UTC

Operational indicators for this CVE are listed under Detection.

Sensor telemetry

First-party evidence of exploitation activity

Aggregate observations show the scale, recency, and distribution of activity without overstating sparse data.

14

Attempts observed

11

Unique attacker IPs

8

Attacker countries

CN · FR · IE · IN · NL · PT · TN · US

1

Sensors observed

Exploitation attempts over the last 42 days

Daily events observed by KEV Intelligence sensors

Updated 19 Aug 2026

0
3
0
0
0
0
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2
0
0
0
0
0
0
0
0
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9 Jul 18 Jul 27 Jul 5 Aug 19 Aug

First observed 10 Jul 2026 · Last observed 18 Aug 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
2
User-Agents
10

Raw values available in Pro and Enterprise.

Virtual patch status

No KEV Intelligence 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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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/2026/CVE-2026-5027.yaml 11 Jun 2026

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

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

EPSS

31.4%

Weaknesses

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') CWE-22

Recent mention · BleepingComputer

Path traversal flaw in AI dev platform Langflow exploited in attacks

Attackers are actively exploiting CVE-2026-5027, a high-severity path traversal vulnerability in the AI development platform Langflow, to write arbitrary files on exposed servers. [...]

Read full advisory

All Mentions

Recent mention · BleepingComputer

Path traversal flaw in AI dev platform Langflow exploited in attacks

BleepingComputer · 10 Jun 2026

Attackers are actively exploiting CVE-2026-5027, a high-severity path traversal vulnerability in the AI development platform Langflow, to write arbitrary files on exposed servers. [...]

Recent mention · TheHackerNews

Langflow Vulnerability CVE-2026-5027 Exploited for Unauthenticated RCE

TheHackerNews · 10 Jun 2026

A high-severity security flaw in Langflow, an open-source low-code platform to build artificial intelligence (AI) applications, has come under active exploitation in the wild, according to findings from VulnCheck. The vulnerability in question is CVE-2026-5027 (CVSS score: 8.8), a case of path traversal that could allow an attacker to write files to arbitrary locations. "The 'POST /api/v2/

Recent mention · TheHackerNews

Unpatched Langflow Flaw CVE-2026-5027 Exploited for Unauthenticated RCE

TheHackerNews · 10 Jun 2026

A high-severity unpatched security flaw in Langflow, an open-source low-code platform to build artificial intelligence (AI) applications, has come under active exploitation in the wild, according to findings from VulnCheck. The vulnerability in question is CVE-2026-5027 (CVSS score: 8.8), a case of path traversal that could allow an attacker to write files to arbitrary locations. "The 'POST /

Potential Proof of Concepts

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

Langflow <= 1.8.4 - Path Traversal to RCE via File Upload

nuclei · Created Unknown

Timeline

From disclosure to observed exploitation

  1. Observed by KEV Intelligence sensors

    Evidence-backed exploitation signal

  2. Indicators of compromise added (13)

    Indicators of compromise recorded

  3. KEV confirmed by The Shadowserver

    Exploitation attested by an external source

  4. Public PoC available

    Public proof-of-concept code published

  5. Nuclei template available

    Scanner coverage available

  6. KEV confirmed by BleepingComputer

    Exploitation attested by an external source

  7. Added to KEV Intelligence KEV Feed

    High-confidence, third-party attested exploitation

  8. CVE published

    Vulnerability disclosed publicly

  9. 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-2026-5027

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2026-5027",
  "confidence": "Confirmed",
  "cvss_score": 8.8,
  "cvss_estimated": false,
  "epss_score": 0.31405,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": true
  },
  "sensor_telemetry": { "attempts": 14, "sensors": 1 }
}

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