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Fencer Vulns
critical 9.8

CVE-2026-33017 kev in the critical feed json

Langflow has Unauthenticated Remote Code Execution via Public Flow Build Endpoint

published 2026-03-17 7 mo ago modified 2026-07-13 3 mo ago also GHSA-vwmf-pq79-vjvx , PYSEC-2026-379 , EUVD-2026-13556

cvss
9.8
version 3.1, NVD
cisa kev
Exploited
added 2026-03-25
epss
96.4%
EPSS 96.4% chance of exploitation in 30 days, percentile 99.8%
public exploits
2
Metasploit, Exploit-DB, plus a Nuclei check

Summary

Langflow is a tool for building and deploying AI-powered agents and workflows. In versions prior to 1.9.0, the POST /api/v1/build_public_tmp/{flow_id}/flow endpoint allows building public flows without requiring authentication. When the optional data parameter is supplied, the endpoint uses attacker-controlled flow data (containing arbitrary Python code in node definitions) instead of the stored flow data from the database. This code is passed to exec() with zero sandboxing, resulting in unauthenticated remote code execution. This is distinct from CVE-2025-3248, which fixed /api/v1/validate/code by adding authentication. The build_public_tmp endpoint is designed to be unauthenticated (for public flows) but incorrectly accepts attacker-supplied flow data containing arbitrary executable code. This issue has been fixed in version 1.9.0.

Patch / fix

cisa required action Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

  • pypi langflow 1.9.0
  • langflow langflow 1.8.2

Timeline

  1. Published
  2. First public exploit (Metasploit exploit/multi/http/langflow_unauth_rce_cve_2026_33017)
  3. Added to CISA KEV
  4. CISA SSVC: exploitation active
  5. CISA patch deadline

Known exploited

Added
7 mo ago
Patch by
2026-04-08 (7 mo ago)
Ransomware
Not known
Required action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Vendor, product
Langflow, Langflow
CISA name
Langflow Code Injection Vulnerability

CISA SSVC

Exploitation
Active, exploited in the wild
Automatable
yes
Technical impact
total
Assessed
7 mo ago

Exploit prediction

96.35% chance of exploitation in the next 30 days, higher than 99.8% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • Metasploit exploit/multi/http/langflow_unauth_rce_cve_2026_33017 Langflow Unauth RCE metasploit exploit, excellent rank, 2026-03-20
  • EDB-52627 Langflow 1.9.0 - RCE webapps, 2026-07-08
  • Nuclei template Langflow < 1.9.0 - Remote Code Execution nuclei detection template
  • medium.com https://medium.com/@aviral23/cve-2026-33017-how-i-found-an-unauthenticated-rce-in-langflow-by-reading-the-code-they-already-dc96cdce5896 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/langflow-ai/langflow/security/advisories/GHSA-vwmf-pq79-vjvx referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 9.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L
CNA 4.0 9.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
GitHub 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
OSV 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
pypi langflow
<1.9.0
1.9.0

Affected products

  • langflow-ai langflow

Classification

Weakness
  • CWE-94 Improper Control of Generation of Code
  • CWE-95 Improper Neutralization of Directives in Dynamically Evaluated Code
  • CWE-306 Missing Authentication for Critical Functionality

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.