CVE-2026-33017: Langflow Code Injection Vulnerability

Should you act?

Exploited: patch now if you run it

CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Yes, if you run Langflow Langflow. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-03-25, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-04-08; treat that as the outer limit, not the target.
• EPSS 24.8%, percentile 98: FIRST’s model estimates a 24.8% chance of exploitation activity in the next 30 days, higher than 98% of all scored CVEs (very high). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes langflow (PyPI) <= 1.8.2, fixed in 1.9.0. Check your lockfile, including transitive dependencies.
• Editorial verdict: Act now. Langflow CVE-2026-9198: Exploited Unauthenticated RCE — Langflow is now the most repeatedly exploited AI-agent builder on CISA's list; any network-reachable instance below 1.10.1 should be patched today and checked for compromise.

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/buildpublictmp/{flowid}/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 buildpublictmp 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.

From the GitHub advisory

Summary

The POST /api/v1/buildpublictmp/{flowid}/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 buildpublictmp endpoint is designed to be unauthenticated (for public flows) but incorrectly accepts attacker-supplied flow data containing arbitrary executable code.

Affected Code

Vulnerable Endpoint (No Authentication)

CISA’s summary

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

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

Product: Langflow Langflow · Assigned by: GitHub_M · Published: 2026-03-20

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Attack requirements: none
• Privileges required: none (no login)
• User interaction: none

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: added 2026-03-25; federal due date 2026-04-08. Known ransomware use: Unknown.
• 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.
• CISA SSVC assessment: exploitation active, automatable yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 24.75% probability of exploitation activity in the next 30 days; percentile 98.

Timeline

• 2026-03-17 — GitHub-reviewed advisory GHSA-vwmf-pq79-vjvx published (critical)
• 2026-03-20 — CVE record published by GitHub_M
• 2026-03-25 — Added to CISA’s Known Exploited Vulnerabilities catalog
• 2026-04-08 — CISA remediation deadline for US federal agencies
• 2026-05-21 — CVE record last updated
• 2026-08-04 — erroneo.us brief: Langflow CVE-2026-9198: Exploited Unauthenticated RCE

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vendor and project advisories, patches

1. github.com github.com
2. Listed in CISA KEV notes (github.com) github.com

Vulnerability records

1. GitHub Advisory GHSA-vwmf-pq79-vjvx github.com
2. CVE.org record CVE-2026-33017 cve.org
3. NVD entry CVE-2026-33017 nvd.nist.gov

Government

1. CISA Known Exploited Vulnerabilities catalog entry cisa.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. sysdig.com sysdig.com
4. medium.com medium.com
5. github.com github.com
6. github.com github.com
7. cisa.gov cisa.gov

All exploited Langflow vulnerabilities · Critical PyPI advisories · Today’s Security Digest