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CVE-2026-33309

Langflow has an Arbitrary File Write (RCE) via v2 API

Critical10.0Public exploitEPSS 13.5%
Published
Updated
Reserved
Assigned by
GitHub_M

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.

Public exploit

An exploit or proof of concept is public: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: a proof of concept is public.

Timeline

  1. ID reserved

    By GitHub_M

  2. · 6 days later

    Published

  3. · 1 day later

    Record updated

Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.

Scores

CVSS scores of CVE-2026-33309, by who scored it
Scored byCVSSScoreVector
GitHub_MCNA (assigner)3.1Critical10.0CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
NVDNVD · Analyzed3.1Critical9.9CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
EPSS (exploitation in 30 days)
13.5% · top 3.5% of all CVEs (7 Nov 2026)
CISA SSVC
Exploitation: poc · Automatable: no · Technical impact: total
Loading the EPSS history…

The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 10.0.

Weakness

Affected products

Affected packages

From reviewed advisories of the GitHub Advisory Database.

References (1)

Sources

The same CVE in the primary databases and aggregators, to check against.

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Record last updated .