NVD / CVE Program· CNA GitHub_M

CVE-2026-33309: Langflow has an Arbitrary File Write (RCE) via v2 API

Noroxi assessment

Priority: Plan (action score 43/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 13.4% (FIRST EPSS); higher than 96.4% of all records.
Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
Fixed version: langflow (PyPI) 1.9.0.

Add it to your regular patch cycle. Upgrade to langflow (PyPI) 1.9.0 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

CriticalCVSS 9.9 · v3.1—No exploit Fix available

Published: Mar 24, 2026
Updated: Jun 17, 2026
EPSS: 13.4% · 96th percentile
CWE: CWE-22

Report tools

JSON

Action score

Plan

Add it to your regular patch cycle.

CVSS: 39 / 40 · 9.9 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 4 / 30 · 13.4%

CISA SSVC decision

Exploitation: proof of concept
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · GitHub_M: 10.0; NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
langflow	langflow	cpe:2.3:a:langflow:langflow

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

langflow langflow1.2.0 and later · before 1.9.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

langflow-ai langflow
- >= 1.2.0, < 1.9.0affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
PyPI	langflow	from 1.2.0 · before 1.9.0	1.9.0

Same product

langflow: all records

Other highest-scoring records for the same primary product.

CVE-2025-3248Langflow < 1.3.0 Unauthenticated RCE via /api/v1/validate/codeKEV
99Now
CVE-2026-33017Langflow has Unauthenticated Remote Code Execution via Public Flow Build EndpointKEV
96Now
CVE-2025-34291Langflow <= 1.6.9 CORS Misconfiguration to Token Hijack & RCEKEV
95Now

Published before and after this one in the same product

← EarlierCVE-2026-27966Feb 25, 2026 · Langflow has Remote Code Execution in CSV Agent
60This week
← EarlierCVE-2026-33053Mar 20, 2026 · Langflow has Missing Ownership Verification in API Key Deletion (IDOR)
24Monitor
Later →CVE-2026-33475Mar 24, 2026 · Langflow GitHub Actions Shell Injection
37Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
PyPI:langflow	1.9.0	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

CVE-2026-50273 days apartLangflow - Path Traversal Arbitrary File Write via upload_user_file
47Plan
CVE-2026-334970 days apartLangflow: /profile_pictures/{folder_name}/{file_name} endpoint file reading
40Plan
CVE-2026-4204849 days apartLangflow: Path Traversal in Langflow Knowledge Bases API
39Monitor
CVE-2026-752464 days apartPath Traversal Vulnerability in File Processing Components Allows Unauthorized File System Access and Potential Remote Code Execution
39Monitor
CVE-2026-8859115 days apartPath Traversal in APIRequest Component via Content-Disposition Header
39Monitor
CVE-2026-7667115 days apartPath Traversal Vulnerability in API Request Component Content-Disposition Header Processing
35Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Impact can extend beyond the vulnerable component (scope changes).

Attack vector: Network
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Changed
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

nvd-secondary

Root cause

A user-supplied file name is joined with the allowed directory, but the result is never checked to confirm it is still inside that directory.

The bug in code

The whole CWE-22 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1const file = path.join(ROOT, req.query.name);
2res.sendFile(file);

Fixed

1const file = path.resolve(ROOT, req.query.name);
2if (!file.startsWith(ROOT + path.sep)) {
3  return res.sendStatus(400);
4}
5res.sendFile(file);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

—

Change log

Fix✗ → ✓Sep 28, 2026, 10:48 PM UTC

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