Known exploited vulnerability · CISA KEV

CVE-2026-33017: Langflow Code Injection Vulnerability

Langflow contains a code injection vulnerability that could allow building public flows without requiring authentication.

CVE-2026-33017

Exploited in the wild. Fix this first.

CISA added it to the Known Exploited Vulnerabilities catalog on 2026-03-25: attackers are using it right now.

CISA KEV: Listed; Added 2026-03-25 · federal fix-by 2026-04-08
EPSS (30 days): 96%; Higher than 99.9% of CVEs · 2026-11-01
CVSS v4.0: 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

What CISA says

Langflow Code Injection Vulnerability

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

NVD description · published 2026-03-20

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.

Full record on NVD

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How to check if you are exposed to CVE-2026-33017

Find every Langflow system you or your clients run, including ones exposed to the internet. Those come first: CISA only lists flaws attackers are already using.
Compare each version with the fixed versions in the vendor advisory below. Where no fix exists yet, apply the vendor’s mitigation or take the system off the internet.
Run a credentialed vulnerability scan to catch the systems you missed, then check that the next scan no longer reports CVE-2026-33017.

US federal agencies had to fix this by 2026-04-08. Everyone else should treat that deadline as a guide: if it has passed, this is overdue.

Affected versions

Versions the National Vulnerability Database lists as vulnerable to CVE-2026-33017. Check the vendor advisory for the exact fixed builds before you sign anything off.

Product	Vulnerable versions
Langflow	before 1.8.2

Timeline

2026-03-20 · Published in the National Vulnerability Database
2026-03-25 · Added to CISA's Known Exploited Vulnerabilities catalog, 5 days after it was published
2026-04-08 · Fix-by date for US federal agencies, passed 207 days ago

Vendor advisories and fixes

https://github.com/langflow-ai/langflow/security/advisories/GHSA-vwmf-pq79-vjvx

Weakness type

More exploited Langflow vulnerabilities

CISA lists 5 exploited Langflow vulnerabilities. The closest matches:

Keep going

Sources: CISA Known Exploited Vulnerabilities catalog (version 2026.10.30); EPSS data from FIRST.org; CVSS and descriptions from the NIST National Vulnerability Database. Checked 2026-11-01. This product uses the NVD API but is not endorsed or certified by the NVD.