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Known exploited vulnerability

CVE-2026-33017

criticalCVSS 4.0 9.3In CISA KEVEPSS 96%Published · langflow-ai

The short answer

CVE-2026-33017 affects langflow-ai langflow and is rated critical (CVSS 9.3). CISA added it to the Known Exploited Vulnerabilities catalog on 2026-03-25: attackers are using it, so patch it first. Fixed versions are published for langflow (1.9.0).

What it is

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.

Weakness: CWE-94, CWE-95, CWE-306.

Severity

9.3 critical

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

Exploited (CISA KEV)

Yes, since Mar 25, 2026

Federal due date Apr 8, 2026

EPSS, next 30 days

96%

Higher than 100% of scored CVEs

How it can be exploited

Attack vector
Network
Attack complexity
Low
Attack requirements
None
Privileges required
None
User interaction
None
Confidentiality impact
High
Integrity impact
High
Availability impact
High

What CISA says to do

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

Affected packages and fixed versions

PackageEcosystemFixed inAdvisory
langflowPyPI1.9.0GHSA-vwmf-pq79-vjvx

Is it in your code? Drop your lockfile into the free vulnerability check, or let vulnerability watch check your repository every day and open the upgrade as a pull request.

Affected products

langflow. NVD's record lists the exact affected versions.

References

Questions

Is CVE-2026-33017 being exploited?

Yes. CISA added CVE-2026-33017 to its Known Exploited Vulnerabilities catalog on 2026-03-25, with a federal remediation due date of 2026-04-08.

How do I fix CVE-2026-33017?

Upgrade to a fixed version: langflow (PyPI) 1.9.0. CISA's 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.

From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.

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