CVE-2026-51888

Published Oct 1, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed

Description

langflow-ai langflow v1.8.4 is affected by: Directory Traversal. The impact is: Arbitrary file write outside the intended workspace or storage boundary.. The component is: src/backend/base/langflow/api/v1/knowledge_bases.py:knowledge_bases-create_knowledge_base-a-live-http-post-to-create-knowledge-base. The attack vector is: Attack surface: HTTP or browser-backed service path. A public-facing upload or HTTP route handler forwards an attacker-controlled path or filename into host file creation without any visible boundary enforcement. ¶¶ A weakness has been identified in langflow-ai langflow up to 1.8.4. langflow contains an absolute path traversal vulnerability in knowledge_bases-create_knowledge_base-a-live-http-post-to-create-knowledge-base (src/backend/base/langflow/api/v1/knowledge_bases.py:51). An attacker can write or overwrite files outside the intended working directory by providing absolute paths in the knowledge base creation endpoint.

Analysis

Technical impact

A directory traversal flaw exists in the knowledge base creation endpoint of langflow. The endpoint accepts a filename parameter and forwards it directly into the host file creation routine without enforcing a boundary, allowing an attacker to provide absolute paths. As a result, an attacker can write or overwrite any file on the filesystem that the application’s user has permission to modify, potentially compromising code execution, data integrity, or system configuration.

Affected Systems

langflow‑ai Langflow version 1.8.4 is affected. The vulnerability resides in src/backend/base/langflow/api/v1/knowledge_bases.py. No other vendors or products are listed.

Risk and Exploitability

The attack vector is remote, via HTTP requests to the public knowledge base creation route. Because the flaw permits arbitrary file write, a successful exploit could lead to the creation of malicious executables or alteration of critical files, resulting in full system compromise. The CVSS score is 7.5, indicating a high severity level. The EPSS score is < 1%, and the vulnerability is not listed in CISA’s KEV catalog, so the current exploit probability is low but non-zero. Until a fix is applied, the risk remains significant.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

n/a

affected

Version	Status	Constraints
`n/a`	affected	—

No data.

Vendor Product Versions

Langflow

Version	Status	Scheme	Platform
`[0,1.8.4]`	affected	semver	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Update to the newest Langflow release that contains the directory traversal fix.
If an update cannot be applied immediately, modify the knowledge_base creation endpoint to reject absolute paths and enforce that filenames are relative to a sandboxed directory.
Deploy a WAF or reverse proxy rule to block HTTP requests containing leading slashes or traversal sequences targeting the vulnerable endpoint.
Reduce the operating system privileges of the Langflow process so that even if an attacker writes a file outside the intended directory, it cannot affect critical system files.

Generated by OpenCVE AI on October 7, 2026 at 07:55 UTC.

Tracking

Advisories

No advisories available

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact High

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.635% probability within 30 days)

Exploitation poc

Automatable yes

Technical Impact partial

References

Link	Providers
https://gist.github.com/Ro1ME/c85f513d1fd702c686cffe061cbf8ef5

History

Oct 7, 2026 8:15 AM Title updated View changes

Type	Values Removed	Values Added
Title	Directory Traversal Allowing Arbitrary File Write in Langflow Knowledge Base Creation Endpoint

Oct 6, 2026 3:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		cvssV3_1 `{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'}` ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Oct 2, 2026 2:45 PM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Langflow Langflow langflow
Vendors & Products		Langflow Langflow langflow

Oct 1, 2026 11:30 PM Title updated. Weaknesses updated View changes

Type	Values Removed	Values Added
Title		Directory Traversal Allowing Arbitrary File Write in Langflow Knowledge Base Creation Endpoint
Weaknesses		CWE-22

Oct 1, 2026 9:45 PM Description updated. Added references View changes

Type	Values Removed	Values Added
Description		langflow-ai langflow v1.8.4 is affected by: Directory Traversal. The impact is: Arbitrary file write outside the intended workspace or storage boundary.. The component is: src/backend/base/langflow/api/v1/knowledge_bases.py:knowledge_bases-create_knowledge_base-a-live-http-post-to-create-knowledge-base. The attack vector is: Attack surface: HTTP or browser-backed service path. A public-facing upload or HTTP route handler forwards an attacker-controlled path or filename into host file creation without any visible boundary enforcement. ¶¶ A weakness has been identified in langflow-ai langflow up to 1.8.4. langflow contains an absolute path traversal vulnerability in knowledge_bases-create_knowledge_base-a-live-http-post-to-create-knowledge-base (src/backend/base/langflow/api/v1/knowledge_bases.py:51). An attacker can write or overwrite files outside the intended working directory by providing absolute paths in the knowledge base creation endpoint.
References		https://gist.github.com/Ro1ME/c85f513d1fd702c686cffe061cbf8ef5