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CVE-2026-33309

Langflow remote code execution

9.9 CRITICALPublic exploitEPSS 1.05%
  1. Published24 Mar 2026

Description

Langflow is a tool for building and deploying AI-powered agents and workflows. Versions 1.2.0 through 1.8.1 have a bypass of the patch for CVE-2025-68478 (External Control of File Name), leading to the root architectural issue within `LocalStorageService` remaining unresolved. Because the underlying storage layer lacks boundary containment checks, the system relies entirely on the HTTP-layer `ValidatedFileName` dependency. This defense-in-depth failure leaves the `POST /api/v2/files/` endpoint vulnerable to Arbitrary File Write. The multipart upload filename bypasses the path-parameter guard, allowing authenticated attackers to write files anywhere on the host system, leading to Remote Code Execution (RCE). Version 1.9.0 contains an updated fix.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredLow
User interactionNone
ScopeChanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected products

Langflow≥ 1.2.0 < 1.9.0

Remediation

Fixed in
Langflow≥ 1.9.0

References

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Frequently asked

Is CVE-2026-33309 being actively exploited?

CVE-2026-33309 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 1.05%.

How severe is CVE-2026-33309?

CVE-2026-33309 has a CVSS 3.1 base score of 9.9, rated critical. EPSS estimates a 1.05% probability of exploitation.

Which products are affected by CVE-2026-33309?

Affected products include Langflow.

How do I fix CVE-2026-33309?

Upgrade affected software to a fixed version, for example Langflow 1.9.0 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-33309 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.