Staging Environment: Content and features may be unstable or change without notice.
Advisory details: pypa / langflow/PYSEC-2026-79
Advisory ID pypa/langflow/PYSEC-2026-79
Aliases CVE-2026-33309
GHSA-g2j9-7rj2-gm6c
PYSEC-2026-79
Summary 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.
Status Published
Exploitability 0.5
Weighted Severity 8.9
Risk 4.5
Affected and Fixed Packages Package Details
Introduced and Fixed Package Commit Patches Package Commit Patches Details
Weaknesses (0)
There are no known CWE.
System Score Found at
cvssv3.1 9.9 https://github.com/pypa/advisory-database/blob/main/vulns/langflow/PYSEC-2026-79.yaml
Reference id Reference type URL
GHSA-g2j9-7rj2-gm6c Other https://github.com/langflow-ai/langflow/security/advisories/GHSA-g2j9-7rj2-gm6c
No exploits are available.

No EPSS data available for this advisory.

Patch URL
There are no known patches.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H Found at https://github.com/pypa/advisory-database/blob/main/vulns/langflow/PYSEC-2026-79.yaml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none

Vector: SSVCv2/E:P/A:N/T:T/P:M/B:A/M:M/D:R/2026-03-24T17:47:04Z/

Decision: Track*

Source URL: https://github.com/cisagov/vulnrichment/blob/develop/2026/33xxx/CVE-2026-33309.json

Source Advisory: vulnrichment/CVE-2026-33309

View SSVC decision tree 
[{'Exploitation': 'poc'},
 {'Automatable': 'no'},
 {'Technical Impact': 'total'},
 {'Mission Prevalence': 'minimal'},
 {'Public Well-being Impact': 'material'},
 {'Mission & Well-being': 'medium'}]